I logged out and it made me create a unique device_tracker to get back in. I’m on the latest version
Have you refreshed your browser?
Happened to me on the android app twice in a row a couple of months ago. Thought it was because I enabled 2FA the first time, but that wouldn't explain why it happened the second time.
As long as you name your device exactly the same as before, your mobile entities (inc device tracker) & automations won't be affected.
I restored a previous backup. It wouldn’t let me name it the same. It said it already existed.
On my iphone? My browser on my PC was unaffected.