It's still happening with the 6.4.3-2 package on s390x. build log:
https://buildd.debian.org/status/package.php?p=grass copied upstream as https://trac.osgeo.org/grass/ticket/2085 Hamish -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org