Recently I've found that I've had a lot of difficulty in interacting with NPC's this patch. For example, taking flight paths, I click where i want to go, and nothing happens. Then it will work on the 2nd or 3rd attempt. The same thing happens for Arena queues for me.

I know this has been happening to at least 1 of my friends, but has anyone else encountered this problem?

Yes I have this problem constantly. Its horrible when leveling because half the time I can't learn my new spells,etc.

I believe there is a blue post which claimed it was because the client said you were at a certain point but the server claimed you were somewhere else or something to that effect. Though I have no idea why this problem arrose in 2.3 and not before if its a problem with my connection.

I have encountered this problem, yes.
I simply try interacting again.

Hate to resurect an old thread but I might have found a possible solution. Where as before I used to spam right click the npc now if I just press it once it tends to work straight away with no problems.