The make/Defs.gmk tries to detect the pandoc binary:

PANDOC := $(shell if [ -r /usr/bin/pandoc ]; then \
echo /usr/bin/pandoc ; \
elif [ -r /usr/local/bin/pandoc ]; then \
echo /usr/local/bin/pandoc ; \
elif [ -r /opt/homebrew/bin/tidy ]; then \
echo /opt/homebrew/bin/pandoc ; \
else \
echo /bin/echo "pandoc not available" ; \
fi )

That elif statement appears to have a typo, it's checking for the presence of /opt/homebrew/bin/tidy instead of /opt/homebrew/bin/pandoc