remake-after-aclocal-m4 is one of the two tests that fail. I've attached the t/remake-after-aclocal-m4.log file.
Thanks. I wonder if this and aclocal-I-and-install fail consistently for you. There is a timing issue with development automake that requires development autoconf (for a one-character fix in autom4te). Info: https://bugs.gnu.org/64756. That's my first guess, since the tests do not fail for me or others (under -j), using development autoconf. Inserting a fallback fix so that dev autoconf is not required is one of the required things for making the next automake release. --thanks, karl.