Yes, those things are a PAIN.
When I got my first Form 3, and when inserting my very first tank, I accidentally left one of those inside in the back left (when facing the printer) of the printer. The LPU crashed into it which then crashed against the limit sensor for the LPU which made lots of awful noises and the printer obviously refused to go anywhere.
I did manage to find it out (which was hard to see a black thing inside a dark place) and noticed the limit sensor was bent from all the pushing and hitting. I bent it back and it has been working flawlessly ever since.
Even after dozens of new tanks, I still check if all 4 foam corners are inside the box or not before inserting the tank. Learn by mistake, that’s life.
Those things should be banned and replaced by something with a fluorescent yellow color and stuck to the box with the hardest glue available!!!