Logged on #Facebook with my partner's credentials to handle Marketplace orders (for my LEGO sets) while she's away at a work conference, then browsed to an Instagram reel for completely different reasons, and #Instagram shows me a banner prompting me to log in as my partner's account.

IT ISN'T THE SAME FUCKING WEBSITE! 🤬

I do understand #Google cross-login between apps because they're all under the same google.com domain, so cookies can work across apps, but between facebook.com and instagram.com? I hate it.