Copied from discord report:

During the Red Eye AI fight on the last phase. Has Fassie ult then swap to Zed to deal damage. Fassie did the first part of his ult animation then didnt do the 2nd part. All the enemies fougt each other and Fassie's ult didn't go on cool down so I just continue to do it for the rest of the fight. I'm guessing this isnt intentional but wanted to report it either way. 

To add onto this after doing it again, seems hes moving to avoid the bosses attacks which causes him to cancel the animation