I had an issue with several defroster lines weren't working on my car. I never had my windows tinted, so this came like this right from the factory. Looking closely at the lines, I didn't notice any damage or parts of the lines removed. Tesla ended up replacing my rear glass under warranty. When looking at the new glass, I noticed that some of the upper lines were slightly discolored. And looking closer, it looks like something (like a piece of paper) was taped to the inside of the glass, because I can see the impression of a wide piece of tape that marked the glass (you can easily tell when the glass is all foggy, even seeing what looks to be foam "squares" which likely was used to space several pieces of glass at the factory. And when Tesla installed it, they removed the paper and tape, peeling the lines where the tape was stuck to.
Luckily, where this happened was on the upper lines, which are the radio antenna lines, and I haven't noticed any issues with my radio reception. So I decided about having to replace my rear glass immediately after they installed it.
Here are 2 pics of the defroster lines not working (lines 3 and 6), along with 1 pic of the radio lines that got partially peeled by the tape.
These defroster/radio lines are definitely very very fragile.
--Cintoman
