It’s a WP issue that’s affecting BP which DJPaul reported in WP Trac https://core.trac.wordpress.org/ticket/16744
Read the ticket though, doesn’t appear that anything will be done about it it is perhaps a BP problem really as BP pulled it’s theme out of the normal WP theme directory where it was originally and should have stayed! WP may have changed things but doesn’t sounds as though it will change it back, tickets 4 months old! so you’ll have to edit locally for the moment, which is far better anyway.
@hnla something you’d like to add here https://buddypress.trac.wordpress.org/ticket/3096 or in a new ticket ?
@mercime and you think there would be any point? The two tickets state their intractable positions. Personally I care little, I don’t ever use this function of WP, I don’t like these functions, they always feel like a security issue waiting to happen.
I suspect that WP devs could fix this, but far be it for someone as insignificant as myself to suggest so.
It is an issue with WP core which just hasn’t been fixed yet.
Guessing this is highly inconvenient and awkward for a whole lot of BP users that aren’t able to run localhost dev sites.