It sounds like a multifaceted failure mechanism that includes battery isolation barriers being crimped under assembly into cases. Overall compression of the battery form factor when assembled and accelerating that failure mode with heat intense rapid charging.
I'm going to be looking else where for my next laptop. The graphics for the $$ spent on the top end machine isn't cutting it anymore. I have had every iteration of MBP since 2010, but I can't see paying top dollar for second tier GPU options.
The graphics options are very weak for a high end laptop. I have a 2015 MBP and I will be looking at alternative plateforms with better GPU options, i.e., I'm done paying top dollar for secretary no class graphics processing