trying to concatenate CRules.isWarmup() to a string crashes server

[bunniewormy]

Doesn't happen on normal build

What works fine:

bool wm = true;
printf('d' + wm);

printf('d' + getRules().get_bool("tutorial"));

What crashes:

printf('d' + getRules().isWarmup());

bool wm = getRules().isWarmup();
printf('d' + wm);

'uwu' + getRules().isWarmup();

This happens both when done in a script or by using console