The only change I'm aware of for Evocation in 2.2 was so you're always guaranteed four full mana ticks, as it was possible to only get three if timed correctly (incorrectly?). It's always possible a fix may affect something else, but there was certainly no intended change. I'll look into a bit further.

It may not matter for much longer though as we're changing Evocation in 2.3 to instead restore 15% of your total mana every 2 seconds, instead of being a Spirit-based mana regen increase.