On Fri, Oct 22, 2021 at 04:31 PM, KWKloeber wrote:

Using the iOS on iPhone X I cannot modify a topic 
by adding a tag.  It doesn’t “take”

It's the same on Android too.

Mark, just to confirm that this is when you view topic properties.  The hashtag is selected but not transferred to the subject line. It works OK on the desktop and mobile site.

Andy