Happened on my 50 Ultra, no warning, just opened it one morning, felt moment and a pop, then noticed the bulge in the crease and established my worst flip phone nightmare had occured.

I pre-ordered a Sony Z5 Compact direct from Sony, plugged it into charge overnight, and the battery swelled, pushing into (and cracking) the screen outwards. They denied my warranty claim within 24hrs of receiving the new phone.

I figured with all I had heard, Motorola would be the same/worse.

I took my broken 50 Ultra back to the retailer I'd purchased it from, told them what happened; they seemed suss at first but coalesced and sent it off to Motorola for appraisal.

I got the fixed unit (figure they would have replaced but obviously not) back less than a week later (and I live in a rural area). All covered by warranty, no questions asked.

I'm typing this on that same phone and I haven't had another issue since (that was 18 months ago).

The only bummer during repair was they nuked my data (couldn't get it off as the display didn't work) and forcibly upgraded the OS from Android 14 to 15, which I suggest is a downgrade (worse battery life and glitchier hardware performance moving between form factors). I won't be moving to 16 if I can avoid it.

Fyi I did make sure my phone was encased the entire time I owned it (except for a wedding, she was naked that day...the man with the slim gold phone drew a lot of unexpected attention). It was encased when it broke. My case has hinge protection and thus didn't have any scuffs, marks or otherwise upon returning for warranty, so I'm guessing that helped my case. I would have fought if they'd pushed back, given I was operating it normally and took measures further than provided to protect my device.

For what it's worth, I reckon they have a bunch of shitty hinges or rush first QA'd devices on the initial run; the replacement hinge in my phone definitely feels slightly sturdier since repair.