Anyone have the issue with the AMS-2 Pro where it won’t feed any filament through the hub, without you somewhat gently pressing that spring-loaded button in the middle where suddenly the filament goes sailing through?
I had disassembled it, found no broken filament, no damage to any of the PTFE tubes - just that the spring-loaded compression wheel at the center of the hub requires a slight pressure now to let filament (from ANY of the slots) feed through all the way? Is there an adjustment that can be made or is this thing so intolerant I need to have Bambu ship me a new hub or ???
Is it possible that the PTFE tube going out of the AMS is not fully inserted or not cut perpendicular? Then the filament might catch at the edge of the tube.
Good thought - but I checked that - along with all the four feeder tubes that go TO the internal hub. It’s like when it hits the hub, it stops, but if I press the release button in the middle of the hub just a little, the filament goes past that little pressure roller and works great.It’s like that spring under the button got stronger all of a sudden and doesn’t let filament through
i have no further idea then 
Seems Bambu had a bad batch of hubs. I had this happen to me. Just send in a ticket explaining your problem and they should mail one out to you. In the mean time try this.
In my case it looked like the two feeder wheels were misaligned.