Also as noted on GN youtube, where they were able to reproduce the melting issue, it requires more than not properly connected connector.
View: https://www.youtube.com/watch?v=ig2px7ofKhQ&t=1467s
namely, connector has to barely make contact AND has to be bent really heavily for it to happen.
only either one of those two wont cause it to happen, you need BOTH.
the main problem with connector is that unless it's in place and locking mechanism has locked, slight back and forth wiggling, like when you do cable management, can cause connector to wiggle out.
so while it is 100% user error, the connector could/should have had some better safety features so that loose connector wouldn't draw/deliver power.