Yup all anyone needs to do is take him into uncollected this month with the juggs before Mister sinister and take a bunch of hits when he’s got a kinetic charge and you’ll be able to see.
I've had the same issue with Juggernauts it appears there a delay when removing unstoppable. You can try it out yourself in this month event (uncollected) just let him complete a 5 hit combo in your block and once you hit him the unstoppable is removed however you immediately get countered by him.
Vs Juggs and there was no special node. Cap had kinetic charge. Like I said, it works but it’s delayed, which screams bug to me. It’s not all fights. But there was a distinct pause between the strike and the removal of Unstoppable, which made Juggs able to counter attack before the second hit of my combo. You are confusing it with the unstoppable heavy that is coming from the node. CapIW will cancel Juggs innate unstoppable ability but will not nullify the passive unstoppable that is attached to the heavy attack in this UC quest before Sinister.
Vs Juggs and there was no special node. Cap had kinetic charge. Like I said, it works but it’s delayed, which screams bug to me. It’s not all fights. But there was a distinct pause between the strike and the removal of Unstoppable, which made Juggs able to counter attack before the second hit of my combo.