I think it'll affect Innervate and Evo and such too.
Basically, chracters have two mana-regen related modifiers:
Mod Power Regen
and
Mod Interrupted Mana Regen
The former is a modifier to base mana regen. The latter represents the percentage of the former that a player gains while under the 5-second rule.
Meditation/Arcane Meditation/3-piece Trans all increase the latter value by 15%. Mage Armor increases it by 30%. The Blue Dragon proc increases it by 100%.
Effects like Innervate and Evocation increase the first value immensely, while also increasing the second by 100%.
The intended effect is meant to be "Your base mana regen goes way up, and for the duration of this effect you get full mana regen while casting."
The problem is that the modifiers to Interrupted Mana Regen were additive and could go past 100, meaning that you gained
more mana while under the 5-second rule than you did otherwise. So if you are a priest with Meditation and 3pc Trans, and a druid innervates you, your Mod Interrupted Mana Regen value is now 130%. That means that you get 30% more regen while casting than you do when you haven't cast a spell for 5 seconds. That was clearly unintended. As an extreme example, if you got an innervate while you had the Blue Dragon proc on you, you'd regain mana as if you had two Innervates at the same time, provided that you kept casting.