I updated my profile a bit ago. At the time I saved with the option to apply it to all communities.
However I just noticed it doesn't appear to have applied to Stack Exchange.
I'd rather not toot my horn too much, but the URL schemes where it worked are:
https://stackoverflow.com/users/{user_id}/{username}?tab=profile
https://math.stackexchange.com/users/{user_id}/{username}?tab=profile
https://stats.stackexchange.com/users/{user_id}/{username}?tab=profile
Compared to SE:
https://stackexchange.com/users/{user_id}/{username}?tab=profile
Any reason this would have failed? It seems like a bug to me.