Drizzt summoned two cats.
1. I encountered this issue on Playstation4
2. I was playing ALONE
3. I was playing as Drizzt
4.Crystal Dream act2
Steps:I didn't do anything different.
When I used Ultimate to summon a cat in a boss battle, two cats were summoned; the Ultimate gauge did not decrease and I was able to summon another one immediately afterwards.
pls See Video.