It was on startup of a clean v1.2. I deleted the v1.1 directory and ~/.local/share/godot just to make sure. A startup of v1.2 as superuser shows some extra warnings:
pure virtual method called
terminate called without an active exception =================================================================
Native Crash Reporting
=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries used by your application.
================================================================= =================================================================
Native stacktrace:
=================================================================
0x9e9ca4 - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x9ea01c - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x9dcac8 - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x9e92ff - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x7f28ddb860f0 - /usr/lib/libpthread.so.0 : (null)
0x7f28dd88f615 - /usr/lib/libc.so.6 : gsignal
0x7f28dd878862 - /usr/lib/libc.so.6 : abort
0x90c6eb - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x247ae76 - ./AfflictionRescue1.2_linux.x86_64 : _ZN10__cxxabiv111__terminateEPFvvE
0x247aeb1 - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x247994f - ./AfflictionRescue1.2_linux.x86_64 : (null)
0x13063b5 - ./AfflictionRescue1.2_linux.x86_64 : _ZN16AudioDriverDummy11thread_funcEPv
0x1dcb300 - ./AfflictionRescue1.2_linux.x86_64 : _ZN11ThreadPosix15thread_callbackEPv
0x7f28ddb7b3e9 - /usr/lib/libpthread.so.0 : (null)
0x7f28dd952293 - /usr/lib/libc.so.6 : clone =================================================================
Telemetry Dumper:
=================================================================
Thread 0x7f28d48c6640 may have been prematurely finalized* Assertion at mono-threads.c:650, condition `info' not met, function:mono_thread_info_current,