garmin

> Some browsers may sign you in automatically without prompting you, so you won't see the wrong address was used.

If that was happening, OP probably wouldn't have said "User B logs in to connect.garmin.com on the web". How would User B get the impression that they logged in as themselves if the browser just signed them in automatically? They clearly know that User A also uses the same browser on the same device.

> I have no idea, but would test disabling the password prefilling anyway

It's not bad advice, but it's just super interesting to me that most tech support, including Garmin support, seems to involve initially denying that there's any problem at all. The default assumption is always that the user is mistaken and/or doing something wrong. I understand that it's expedient to do so, but it's also frustrating from the user's POV, when they are sure that there is a problem.

I'm sure we've both been on the other side of that, where we spend minutes, hours, days, or weeks trying to convince Garmin, some other tech company, a coworker, or a manager that some technical problem is in fact a problem.

So I'm not 100% sure what's happening here either, but I think it's premature to make an absolute claim such as:

"This is not Garmin's fault, though. It is fault of your browser storing the logins and passwords for diverse websites"

It sounds like you're completely dismissing the possibility of a Garmin bug right off the bat.

Again, since Garmin has absolutely had much more severe bugs where users could access activity information of someone who had never even used their device, I don't think it's so crazy to believe that a similar [but less severe] problem was happening here. Those severe problems were caused by inappropriate caching, and it's not a stretch to imagine that inappropriate caching could be the cause here as well.