It has nothing at all to do with having a digit. An invalid pointer is dereferenced within the error-text generating code because the line has neither a pre-resolved function nor a parameter (i.e. because pre-resolution of the function failed; i.e. the function doesn't exist). As with any invalid dereference, whether you get an app crash depends on seemingly random factors (anything which affects what the invalid pointer points to).
It will be fixed.