I have had my hybrids for about the same amount of time as you have, and I definitely have burns on the upper and lower chamber housings. The replacement volcano S&B sent me later had a new replacement chamber housing which, as far as I can tell, is identical to the one I originally received. The tension and pliability of the plastics is virtually the same. The appearance and coloration is the same, although I haven't thoroughly examined it.
So, after one week of getting the chambers out of their housings right after every session I am seeing no plastic damage anywhere, and I feel really good about this. On one occasion I forgot to do that step (because it was my first ever kief whip session from 360-430° F - more on that later). I did have the chambers apart and off the hybrid after the session, but it was left that way for maybe 5 minutes before I remembered it (because I was high).
And now I have a very small burn mark on my new lower chamber. I have cataloged that damage and since done similar temperature range whip sessions with kief and immediately removed the chambers afterwards. I see no further burns on the new plastics from those sessions whatsoever.
Overall, it looks like taking the chambers out of the plastic housings asap, and maybe having the chambers on the hybrid at around 5 minutes or so (like the manual instructs) is the best precaution to take if you want to avoid burning plastic. As you can see I'm trying different temps and using kief more so I can provide better information, so if there is anything you want me to try let me know.
Doing a whip session at 430° F the first time was outstanding. Because my tolerance doesn't take a 50° range of ingredients into account it hit me hard, but I couldn't hang with that vapor for long after getting up there. Maybe two minutes. I've said it before and I'll say it again, this vape is a beast.