I have a suspicion that something changed with the latest code update a few days ago (early January 2022) with respect to the interaction between Linter and table parsing and pipes, or possibly just with the {{!}} magic word used in place of a pipe. I fix Linter syntax errors, and the following code on template documentation pages was not causing an error last week and is causing an error this week:
{| |- |colspan=1 align=center| ''When your text uses a {{!}} pipe:'' |}
I have a demonstration in my sandbox showing that the code by itself does not cause Linter errors, but when it is added to a table, it causes Linter errors (two missing end tags or one missing end tag and one stripped tag) that are consistent with the parser thinking that the pipe is starting a new table cell, thereby leaving the italic markup orphaned twice. As you can see in my sandbox, the text is rendered just fine. These errors were not detected last week; I think they may be new false positives.
Does anyone know of any code changes that may have caused this change?