After casting EA there is timer for 1 round before it can be casted again, otherwise it's casted with no effect.
This does not work everytime.
Example:
Hasted elementalist starts with EA, then casts some spell (tried a lot of various spells - no difference), then attempts another EA on the start of a second round, everything was in quee so there is no chance for delay.
Second EA should already be effective, is casted at the begining of second round as third spell, but not everytime such approach works.
Tested many times and success rate of EA feels like 50%. Makes spell very unstable.