X_ERROR_FIX_INVALID
Means
an error's fix line is not a runnable instruction
Typical cause
the errors step read a fix: that is empty, or one that advises (check, make sure, try, see the docs) with no command, call or file path in it
Fix
the fix names the offending <file>:<line> — rewrite that fix: as a runnable command, a call, or an edit naming a file