Black shows damage more, so it may be possible others are experiencing warping too and it's not as noticeable.I can not find the post that showed a black van with damages side walls due to the spray foam. Very noticeable in the picture as I recall. Just need to use someone that has experience. It is a risk.
Do not know if there are any corrosion issues.
Probably the best way to insulate if you avoid the panel damage issue. ....cut....
Are they claiming that the insulation warps the sheet metal between adjacent ribs, or is it about foam expanding between the rib and sidewall?