My 2nd watch is a GL serial number not sure what the first was. Had it 3 weeks now and worn pretty much every day, multiple charges etc and no bubbles so far.
Sent the watch back on Thursday and received and email yesterday saying they had looked at it and a replacement will be sent out today. Have to say that's very good customer service! (providing I actually get the watch!!!)
I picked my new watch up last week and within a day its done exactly the same. Good job it has a 2 year warranty! Love the watch but not impressed with the screen 'bubbles'