The workaround I’ve found is to type <kbd><kbd> and add in the / last. You can recover the table with Ctrl+Z, sometimes you need to use it multiple times.
The same also happens typing in <></ and text in the first tag. It doesn’t happen when typing <></> and then filling the first tag. Anything in the second tag has no effect it seems.
This also happens typing <a</ and adding the > after a. It doesn’t happen if the closing tag is complete.
This sometimes happens typing a></ and then completing with the < at the front. It didn’t seem to happen in the header row (also containing some of these tests…), but it happened in rows below.
Overall it seems to rely on the closing tag </ lacking a closing angle bracket, and then forming an opening tag or there being an opening tag and forming the </ of a closing tag. Contents of the closing tag other than the ending > have no effect.