astropy/astroquery#2111 (comment)
I think the problem is there is no Sphinx directive defined for the new .. doctest-remote-data:: directive in https://github.com/astropy/pytest-doctestplus/blob/main/pytest_doctestplus/sphinx/doctestplus.py . Hopefully the implementation of .. doctest-skip:: would be a good example to follow.
So, in a way, #137 was incomplete. Perhaps instead of testing that PR in astropy before merge, we should have also tested it in astroquery.
If a fix cannot be done soon, we might need to revert #137 and do another bug fix release, and then re-apply it in the future together with the new sphinx directive. 🤔