Building on this:
1) Did you have any proc trinkets equipped? Were the procs active?
2) As you were spamming Jab, your auto-attack was active (I'm assuming). Was Tiger Strikes active during FoF?
3) Did you have a Combo Breaker proc active?

We should eliminate as many variables as possible, and I'd start with procs and the spell queuing system as potential sources of unexpected interactions with an ability.

I'd also recommend using weapons with no stats on them, both a 2H and a DW set (vendor grays or whites work well). That way you can swap between the two and have identical stats minus the attack speed. Any variance in # of hits between the two weapon sets could then point to a potential culprit. Do note the attack speed on each weapon, or simply report the weapon(s) used during the test.

Ok I hope I have usefull data now!

I used an short staff with 3.37 Dps and changed my equip so that I am below the problematic haste 'cap' and above this 'cap' when I use my Jade Bandit Figuirine.
So I just have to use my trinket to get 4 instead of 5 hits!

My Stats:
AP 24.027
Weaponspeed 2.01 (without Jade Bandit Figurine) / 1.87 (with Jade Bandit Figurine)
Haste +13.30% (without Jade Bandit Figurine) / +21.76% (with Jade Bandit Figurine)
Hit 9%
crit 20.52%
expertise 6.79%
Mastery 12.93%

In my tries I attacked Raiders Trainings Dummy from behind.
I just used Chi Brew and Fists of Fury.
So there was no other procs/buffs/debuffs or other stuff!

Results:
1. try just chi brew + FoF + jade bandit figurine
4 hits
haste +21.76%

2. try just chi brew + FoF + jade bandit figurine
4 hits
haste +21.76%

3. try just chi brew + FoF + jade bandit figurine
4 hits
haste +21.76%

4. try just chi brew + FoF + jade bandit figurine
4 hits
haste +21.76%

5. try just chi brew + FoF + jade bandit figurine
4 hits
haste +21.76%


6. try just chi brew + FoF
haste +13.30%
5 hits

7. try just chi brew + FoF
haste +13.30%
5 hits

8. try just chi brew + FoF
haste +13.30%
5 hits

9. try just chi brew + FoF
haste +13.30%
5 hits

10. try just chi brew + FoF
haste +13.30%
5 hits

Raider's Training Dummy FoF test results:

using [Screaming Tiger, Qiang's Unbreakable Polearm]
I used no trinkets other than [Windswept Pages] which I needed to get near the supposed FoF haste cap. To get to the different haste percentages I unequiped some gear, because of this I missed or got dodged sometimes, but ofcourse I counted that as a tick aswell.
I had my two own buffs up (5%crit and 5% agi,str,int), no other buffs or debuffs.
Before every FoF I jabbed a couple of times to get the trinket proc, then made sure I had no mastery procs up. Then I waited without melee'ing untill I was out of combat, and then did a FoF (while trinket proc was still up ofc).
The haste values (% and rating) are what I saw on my character tab. Not the total haste (cause that includes the 40% from using a 2-hander) but the line that says for example: "Haste 2,744 (+6.46% Haste)"
The 2 haste ratings that are on the edge of 4 and 5 ticks I tested multiple times, with the same result every time.
(for some I forgot to check the rating)

14.16% (6018) -> 5
14.19% -> 5
14.23% -> 5
14.26% (6060) -> 5
14.33% (6091) -> 4
14.42% (6130) -> 4
14.46% (6145) -> 4
14.50% -> 4

These results were consistent every time. So I do believe this problem has to do with haste


edit: I also made a topic on this issue on the wow eu forums: Fists of Fury not working as intended - Forums - World of Warcraft And I submitted a bug via the ingame bug report system, I don't know if it helps if more people do this, to get their attention on it?

I can confirm this, but with dw, 0 buffs, 0 debuffs, Raider's Training Dummy.
I have the EXACT same haste as Xan. 2.29/2.30 Attack Speed
5651 (13.30%) 20 tests with Chi Brew = 5 hits 100% of the time.
9246 (21.76%) 20 tests with Chi Brew = 4 hits 100% of the time.

It seems you are still using the trinket tooltips from wowhead, which are wrong for pretty much every proc. I would suggest you check the actual tooltips in-game and re-do your calculations.

EDIT:
Bottle of Infinite Starts proc
LFR - 2866 agility
Normal - 3236 agility
Heroic - 3653 agility

Jade Bandit Figurine / Hawkmaster's Talon on-use
Normal - 3595 haste

Terror in the Mists proc
LFR - 6121 crit
Normal - 6908 crit
Heroic - 7796 crit

Zen Alchemist's Stone proc
Normal - 4041 agility

Oh damn, you are right!

I allready had the good values for Hawkmaster's Talon and Jade Bandit figurine and the Zen Alchemist Stone. But my values for the Bottle and Terror were wrong
To be sure I also checked values for the other trinkets, which were all ok. The only thing I'm not sure about is the Jade Bandit Figurine on LFR mode, maybe someone has it and can check it?

Updated it now with the correct values, and damn, the Bottle of infinite stars is so much better now... That much agi up for 20 out of ~50 seconds, crazy..

Link to the trinket post: Windwalker (DPS): a flurry of tender fisting.

Thanks for pointing this out to me Crevan!

You're welcome.

Regarding the Jade Figuring from LFR - I tend to think it doesn't exist, just like every other heroic/LFR trash epic data-mined by wowhead before Pandaria. Unless someone links to the armory of a character actually wearing it, I'd suggest you just remove it from the list to avoid confusion.

The Bottle is really, really great. With an uptime of ~45%, we're looking at around 1456 averaged agility (normal version).

Hm.

With zero haste, FoF has an initial tick at 0s, and then a 4s channel for additional ticks at 1s, 2s, 3s, 4s.

Testing in this thread has shown that the 5th tick is dropped at around 14.3% haste. At this level of haste, things take 1/(1 + 0.143) = 0.875ish of their base time, so the 4s cast of FoF is pretty much right at 3.5s. Vishiz also reports getting only 3 ticks at a 2.4s cast, so perhaps the next cutoff is at 2.5s? That would suggest that they're hasting the channel time, but the ticks are not getting hasted correctly and are dropped when the channel gets too short.

Time for some predictions to see if this is right!

If the first cutoff is exactly at 3.5s, that's 14.286% haste, so you'll get 5 ticks at 6071 rating and 4 ticks at 6072.

To reach 2.5s you need 4.0/2.5 = 60% haste, which if you get it all from gear is 25500 rating. That's probably not a concern for most people at the moment.

Bloodlust, though. It's worth 30% melee, ranged and cast speed, and it's multiplicative with gear-haste. With Bloodlust up you'll never be able to get a 5-tick FoF, as even with zero haste you'll still only be channeling for 3.08s, well under the 3.5s limit. The 2.5s cutoff is also a concern here; you need a 1.6 multiplier to run into it, so with the 1.3 from lust you only need another 23.07% haste from gear, or 9808 rating. As Vishiz saw, this is very much in reach; 6.2k on gear and a 3.6k trinket will get you there.

I don't feel like I have enough data to be completely confident at this point, but this all seems pretty plausible to me given what we have so far. If anyone wants to test my predicted rating numbers (6071/6072, 9807/9808 with lust) it'd be very appreciated; otherwise I'll see if I can rope a buddy into helping me test it over the weekend.

There are some new datamined changes on the PTR, main pve one for ww monks is the change to Ascension, the new text reads "Increases your maximum Chi by 1, your maximum mana by 15%, and your energy regen by 15%.".

Second change is that tiger palm is no longer 3 stacks, but only 1 stack for 30%.

Ignoring the possible GCD cap problems with 15% more energy regen, quick napkin math suggests it should provide a damage increase over 1 extra chi every 22 sec. Would be interesting to run a simc on it I guess.

I just read the news on mmo-champion. 15% energy hast would be about 1.5 energy/s. Am i right? You would get an extra Chi every ~13 seconds (26,666 sec for 1 jab)

Just calculated it in my head

I really can't see us to cap our energy again with the TP "buff"

unfortunately i have no idea how to make tests with sim and this stuff