"Should temporary indentation be ignored when centering?"

I raised this question on the mailing list.

https://lists.gnu.org/archive/html/groff/2023-05/msg00079.html

I got one vote of support and no other comments.

One question remains: should we "ignore" a temporary indentation by utterly disregarding it, or by holding it in abeyance until centering (or right-aligning) ends?

The former would be less disruptive to existing documents (and easier to code), so I propose to do that, along with issuing an diagnostic.  I propose for the diagnostic to be an error, not a warning, in part because we have no existing warning category that fits this scenario well.    But also because I have few compunctions about throwing users hard errors when their inputs demand nonsense.

And this scenario is patent nonsense as noted at the link above.