Not possible to activate Gisa ability during my turn or any turn
During my main phase of the next turn after having summoned "Gisa, meneuse de goule" (french), it is not possible to use her ability. Nor during any other turns afterwards.
I had the same issue, it seemed like night turned to day and her ability was skipped. There were two monsters banished too that i should have gotten.
Creatures that are exiled do not return to the battlefield with decay.
Only the exile part works