Thank you everyone. Please disregard my last “Update” (the one where I incorrectly concluded that moving the wire once it’s booted doesn’t cause the power to get lost). My description from my first post is the most valid one.
I double checked my solder points and they seem solid. I cleaned it real good with some 99+% alcohol, dabbed it with flux and even added a little solder (so it’s a little blobby, but no connections touching, and it looks pretty solid).
I hit the 5 points on the usb power, and even the housing mount points (or whatever they’re called) on the board.
Unfortunately, the same problem exists stlll. I created a video if that’s helpful at all (about halfway into the video I zoom out and its more apparent what the problem is, I think):
I will email support and see if they have any recommendations. A replacement would work, but if there’s anything I can do to save the hassle of shipping a single on/off shim across the world I would be happy to try it :).
Last thing worth mentioning: it appears both the good working shim and the one with this problem have about equal “wiggle room” for the USB port. So the bad one isn’t extra loose or anything.