Upon further investigation, this was not the answer after all. I made the decision to remove the embedded ACF from my theme and install it standalone, and the problem is still happening… on the front end, the CSS is loading properly, but on the back end, the URL it’s requesting is this (parts in all-caps edited for privacy):
https://DOMAIN/wp-content/plugins/var/www/PATH/wp-content/themes/THEME/blocks/tile/tile.css?ver=6.2
It may be worth mentioning that this is a Multisite installation, although I don’t think that has anything to do with it.
