Getting backtraces is a bit more coder oriented, though per se doesn’t require that much coding abilities.
Requires first gdb, mentioned there for example:
After that I’d check the pid of ngfd and do ‘gdb -p <the_pid>’, in gdb ‘thread apply all bt’ followed by lots of stuff. There should be some hints about installing debugging symbols which will enhance the output, not all are needed but the ngfd related ones should be the most important.