Bubble on my vivosmart 4

I got a similar bubble. I think is a feature!

TLDR: contact Garmin, they'll exchange it even if you've had it for a while.

For me this seems to happen about every 15 months (1.25 years); I've just received my 2nd (free) exchange now and my original purchase was 2.5 years ago. If you don't want to spend too much time without it, ask support about express exchange. You will have to front a ridiculously high amount on your CC, but they will send you the new device first and then you just send them back your old one (they also provide the free return label (at least here in Canada); they reimburse the déposit 1-2 weeks after they get the device back.

BTW, by "ridiculously high amount" I mean almost twice the device's actual cost, not kidding, I had to front 263$CAD for a device that sells for 145$CAD on Amazon. 

I had this happen on my first vivosmart 4. They exchanged it for a new one. My 2nd one did the same, but eventually popped and tore...may see if they'll replace it. It is out of warranty, though.