Check the contents of the /storage/cache/.cores/ directory - the core file names should include the program name.
eg post the output of
When you notice that a new core file had been created it'd also be useful to post your journal - that should contain some additional info what crashed, and maybe why. run the following command and post the output:
BTW: probably the number one reason for unexplainable crashes on RPis is a bad power supply. The official RPi power supply is known to be good, use that if in doubt.
so long,
Hias