While I had my AMS apart for maintenance, I noticed that the first stage feeder funnel was able to move quite a bit sideways on its pivot shaft. While the filament should straighten this out when it's loaded, it can't hurt to prevent it from moving sideways at all.

Here is a video of the wobbling:

And here is a video after fitting the spacer:

I have been using a simpler version for a while now but they were difficult to install, so I redesigned the spacer so it's thicker and has a tab and angled part in the split so they can be easily installed using a pair of needle nose pliers. You don't need to remove any part of the AMS to install these, apart from the filament spool. The feeder will now stay perfectly aligned with the knurled gear all the time.

I printed these in PETG, as it flexes better than PLA or ABS.

Please let me know in the comments if you have any issues installing, or if they work for you too :)