Here is a bug I filed on Arma 3 crashes:

https://feedback.bistudio.com/T119144
Here is the work around for the crashes (Also listed in the bug):

Workaround I discovered to avoid the game crash…
*do not use Arma 3 native game launcher*
*use known good, custom tbbmalloc.dll from here:https://github.com/fred41/tbbmalloc_arma/tree/master/binary *
*install tbbmalloc.dll, by pasting to your ‘.\Arma 3\dll\’ directory*

Launch via steam with these parameters: -nolauncher -useBE -nosplash -skipintro -world=empty -noFilePatching -cpuCount=4 -maxMem=4096 -exThreads=7 -high -malloc=tbbmalloc -enableHT -mod=@Exile;@Ryanzombies
Attempt to join target server (my case: moosepuncher.ddns.net:2582)
*download mpmission*

Result: Game loads without the game crash issue.