The DAMs are not, in my opinion, entitled to keep their own counsel
about why they refuse to approve a new-maintainer applicant who has
passed all the other checks, by "losing them in the system" for several
months. At the very least, the applicant's AM should be informed of
this, and the applicant's status should be placed "on hold". In most
cases, I doubt extreme discretion is warranted, and the reason for the
applicant being placed on hold should be publicly viewable at
nm.debian.org.
Or perhaps this phenomenon is so common that all applicants who are
waiting on DAM approval for more than, say, 30 days should
automatically
have their status changed to "on hold", with an explanation of "unknown
(awaiting DAM feedback)".