Kind of at a loss here,
tried disabling a bunch of plugins & restarting one by one to see if anything would fix it but it doesn't seem to help.
Whenever going to Edit Profile (whether my own or someone else's), if Allow Multiple Badges is disabled, I can see the dropdown menu just fine, however, if Allow Multiple Badges is enabled, the menu appears for barely a few milliseconds before disappearing, and obviously nothing can really be edited properly this way.

No errors in console either. I just have no idea what's causing this or even how to debug this.