@wiesshund
I saved a test.vpx table with your script tests if you want to test more.
Thanks for your time and patience guys! 
ok make a copy of a table in question, so as to not wreck the real thing
use an unmodified crashing copy
set leftmagnasave in the table1_keydown sub to do
controller.stop
now set the right magnasave to call nvrampathexit
comment out the nvrampatch in the table exit sub
Ok now purpose of this is
ok start table so it is on ball 1
see if hitting right magnasave, with ROM running causes during play or not
if no crash, wait 10 seconds then exit the table
if still no crash on exit
restart table, tell me is it on ball 1 still
Ok now if it DOES crash on any of the above
restart table
start ball 1
hit left magnasave, which should halt vpinmame
wait 10 seconds
then press right magnasave
then exit table
See if there is any crash during that sequence
if no crash start table again and see if it is still on ball 1 or it starts clean.