Invalid mask length followed by segmentation fault

[pdo]

What is the full command you gave it?

./hashcat -a 3 -m 10400 -D 2 '$pdf$1*2*40*-60*1*16*81e541e751de6bd733a82ea38386eb96*32*18c398bb7xxxxx496de999c518cf240fbd157616ce380cdb501e73cff9d3d4a8*32*9xxxxxxx729748bee8fdac2abxxxx2bcd65b3bedcxxxxxxa5a202309ba1be7' ../some_random_old.pdf

also tried without -D 2 and with addtional -O
it doesn't matter if run on GPU or CPU

This command means "use the contents of ../some_random_old.pdf as my mask definitions", which is almost certainly what you intended.