Yup it crashes under Linux. It looks like an invalid memory address call, you properly have a memory leak or calling to illegal memory (eg. outside of your process).
Please, can you provide the Linux version with debug symbols (debug build!)? That would be the only way to debug this issue in more details. Maybe I can help you.
I can't get more output (due to the fact No symbol table is loaded.):
❯ coredumpctl gdb 39346
PID: 39346 (fluxcaves.x86_6)
UID: 1000 (melroy)
GID: 1000 (melroy)
Signal: 6 (ABRT)
Timestamp: Tue 2020-09-22 00:09:22 CEST (7min ago)
Command Line: ./fluxcaves.x86_64
Executable: /home/melroy/Downloads/108_Linux_Full/fluxcaves.x86_64
Control Group: /user.slice/user-1000.slice/session-c1.scope
Unit: session-c1.scope
Slice: user-1000.slice
Session: c1
Owner UID: 1000 (melroy)
Boot ID: 027f3899cd954aa3b420d005aa403df1
Machine ID: f802396639df483aba14581a3628b511
Hostname: melroy-pc
Storage: /var/lib/systemd/coredump/core.fluxcaves\x2ex86_6.1000.027f3899cd954aa3b420d005aa403df1.39346.1600726162000000000000.lz4 (truncated)
Message: Process 39346 (fluxcaves.x86_6) of user 1000 dumped core.
Stack trace of thread 39368:
#0 0x00007fc0e579c18b n/a (n/a + 0x0)
Backtrace stopped: Cannot access memory at address 0x7fc08b7fc8f0