The stack trace looks very much like it would be the effect of https://savannah.gnu.org/bugs/index.php?59202, fixed in https://git.savannah.gnu.org/cgit/groff.git/commit/?id=c788cf8c6bbe939fa11f7ec032e525a7e33f41b6.
The stack trace looks very much like it would be the effect of https:/ /savannah. gnu.org/ bugs/index. php?59202, fixed in https:/ /git.savannah. gnu.org/ cgit/groff. git/commit/ ?id=c788cf8c6bb e939fa11f7ec032 e525a7e33f41b6.