FWIW I just tried to compile Geany master with Clang as well as with [what seem to be Fedora's hardening flags](https://fedoraproject.org/wiki/Changes/Harden_All_Packages), yet I still can't reproduce. I also tried to run in Valgrind's memcheck in case it was a memory access error that was simply not caught by the system because of different build or runtime settings, but that didn't show anything either.
I also installed OpenSansEmoji, which didn't change behavior either.