I have my Bambu A1 set up in a very tight space, so I made use of the AMS Micro by emics to mount my spools vertically.
The printer is able to reliably load and unload filament from all four spools, but during printing (especially slot 4, the topmost spool), particularly after retractions, the extruder will be unable to re-insert the filament and will throw an "extruder is not extruding normally" error. I can manually push the filament in until it's grabbed by the extruder after which the print will continue normally until the next retraction.
The spools spin freely on the stock AMS hubs and the PTFE tubes are short and not worn. Any advice would be most welcome
Potentially rig up some PTFE tube holders that stick to your wall to ensure the filament enters the AMS motors' yellow areas at a perfectly straight angle, I bet the filament is just getting "sticky" with any drag on those parts.
A good idea, I'll try to rig up some magnetic tube holders to keep it aligned