I made an edit to https://commons.wikimedia.org/wiki/User:Pine to add a category, and was surprised to see that this edit replaced Pine's userpage with just that category (sorry Pine!). It looks like this was because Pine has a global userpage on Meta ( https://meta.wikimedia.org/wiki/User:Pine ) that was replaced by my local edit.
This shouldn't happen. An edit to a global user page on a local wiki should result in either:
a) A warning notice explaining that this is a global user page, and that it shouldn't be edited on this wiki
b) A redirect to the user page on meta
c) The edit being redirected to meta-wiki, and taking place there
d) The edit on the local wiki being applied to the global page, rather than replacing that global page.
Please can the UI be improved/fixed here?