Weird. Is your wife's phone nearby by chance? The only time this happens to me it's because we are both walking to the car together and her phone unlocks it before mine does.
And why would that feature rely on a phone in the first place instead of letting the driver change the profile when getting behind the wheel? Or e.g. use a fingerprint sensor or interior camera (which some of the Teslas do have)?
That sounds like some software guy somewhere didn't realize that those seats in the car aren't only for carrying air but that actual people or, gosh, occasional other drivers ride in them too.
Sadly this is rather symptomatic for many things coming out of Silicon Valley (not only Tesla).
It needs to let you select the seat _from the door_ before getting in, without access to the touch screen, else someone 6ft getting in after someone 5ft is in for a miserable time.
Even if she were near, I'd expect it to select her profile and let me select mine. Instead it deletes my profile entirely and I need to reconfigure my seat, mirrors, and any drive settings that are now at default.
There's a setting I just noticed for the first time this morning that lets you define a phone as the "primary" device - the description in the UI suggests its to prevent issues like you described. I'm not sure how long that feature is been there, but my phone is set up as the primary, and I've not had any weird profile issues. To be fair though, my wife rarely ever drives the Model 3, so we've had fewer chances to see any issues.
That sounds like some software guy somewhere didn't realize that those seats in the car aren't only for carrying air but that actual people or, gosh, occasional other drivers ride in them too.
Sadly this is rather symptomatic for many things coming out of Silicon Valley (not only Tesla).