Setting Custom Field Value during Reply or Commnet

Possible I missed this in the archive, but wasn’t sure what to search on.

Running 3.8.1. We have a custom field “Category”. I just noticed that when
replying or commenting and setting a value for that custom field, the value
doesn’t seem to be saved.

Can anyone confirm that? I don’t believe I’ve customized the Update.html
file so would be interested to know if this is a real bug or our install.