Not 100% sure this is what is happening, but it's my best guess. I've had magic carpet cancel on this hero coinciding with the pop-up showing who my turret is doing damage to.
Reproducable by placing a level 2 turret and using carpet before it shoots. Seems that this bug doesn't occur until you get level 2 turret, and only occurs if the level 2 turret shoots for the first time after you are on the carpet.
This happens to me too, in almost every McGinnis game since my current build contains Magic Carpet as a priority.
Can't say if turret T2 upgrade has anything to do with it since I have not paid that much attention to my skill levels when it happens.
This happens every time you apply a NEW debuff to enemies ( turret applies slow, seven stuns someone ) and buff to allies ( someone walks into your heal station ) with innate character SKILLS. That's why you have problems recreating it. It's such a cool item, please remove this bug so we can get clear data how powerfull it is.