BuddyPress.org

Looks like the function is already in your bp-custom.php, which is not part of standard Buddypress. Can you check in the file if it’s the exact same code?

If so, how did it get there…?

If it’s not the same function, you can probably fix the problem by search/replace in the function: synchro_wp_usermeta -> custom_synchro_wp_usermeta

I don’t remember if I replaced an existing function with the same name. Buddypress did have a function to update wp_usermeta when profile info is updated, but I think that one had another name.