You can add logging using the Browser object btw, I find that helpful to see if what I'm expecting to be triggered or picked is correct.
So this sounds like when you press B it is sending through the name of the powerup overlapping slot 1 instead of slot 2. Sometimes the order in conditions matters, try moving Slot_ID= to the top of the condition above 'powerup is overlapping slot' to see if it makes a difference.
If that doesn't work there are other possibilities like both powerups have the same name even though the animations are different. That's why the Browser logging I mentioned is good, you can see what powerup.UID is picked, or what parameter is actually passed through the function, you can log these things.