https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95053
--- Comment #1 from Jürgen Reuter <juergen.reuter at desy dot de> ---
I shrank the example even further:
SUBROUTINE MNSTIN
132 FORMAT (' UNIT',I3,' ALREADY OPENED WITH NAME:',A/
+ ' NEW NAME IGNORED:',A)
RETURN
END
It looks like it is the combination of integer format with this special form of
character line continuation.
