crash report
latest.log
It still crashes under the same conditions, not to sure why.
Like before adding quicksand fixes it.
I found a potential fix:
replace the "optional2.isEmpty()" in SandingScene lines 45 and 47 with "optional2.isEmpty() || optional2.get().size() == 0"
it appears isEmpty() doesn't check if the list is empty so checking against its length should work (I tested it).