I found out that /cores directory was mounted as read-only file system. I used DiskUtility to fix that such that /cores was writeable. Unfortunately still no core files. I tested with a very simple program that called abort() immediately after starting the main function. I have set ulimit -c unlimited and tested with launctl to set core limit there unlimited as well. Still no success. This is extremely disturbing since it means that I cannot debug my application. It is impossible to figure out why a call to pthread_cond_signal fails with Bus error without having access to a core file.

Seems like the 2 terminals I had created, one for Rosetta and one for ARM64 had been squashed and only the Rosetta terminal was remaining. By changing the terminal to use ARM64 it seems the problem disappeared.