Hey Paul,

thank you for your effort in reproducing my issue.

1.) I exported the TM to an .tmx format, opened it in notepad++ and just randomly looked for an entry that I wanted to change. For example:

<tuv xml:lang="de-DE">
<seg>Sometext / Othertext</seg>
</tuv>
<tuv xml:lang="en-US">
<seg>new Sometext / Othertext</seg>
</tuv>

The "/" just happend to be in the segment, doesn't mean anything important.

After the edit I saved the file and imported it back into the TM that I exported from. After the import, in the "translation memory" window in SDL Trados it showed me the change. But when I clicked the referring segment in the editor, it didn't show me the changed entry at all. In the concordance search however it finds the new edited entry.

What I noticed in the meanwhile as well: 

-  If I manually change the segment status to "translated", it THEN seems to find the TM Match and shows it to me.
[edit]
- if I change it back to "draft" it again doesn't show me the TM Match.
Can you conclude anything out of this information? Maybe I have some wrong settings, I don't know.

However, it comes with an "AT" Symbol, but shouldn't it be a 100% Match? Or at least no AT at all?

2.) In the source segment aren't any tags, just the "/" symbol. 

3.) I'm using a Project TM, however it seems the TM actually has the changes in it. I just can't see them in the editor or more precisely in the "translation results" window where it normally shows TM Matches. 

It seems multiple users struggle with similar issue. The following thread at proZ for example seems to referring to a pretty similar matter:

https://www.proz.com/forum/sdl_trados_support/327974-studio_2019_doesnt_find_matches_in_the_tm.html

Hello Christian Schmidt 

Christian Schmidt said:

It seems multiple users struggle with similar issue. The following thread at proZ for example seems to referring to a pretty similar matter:

https://www.proz.com/forum/sdl_trados_support/327974-studio_2019_doesnt_find_matches_in_the_tm.html

I doubt this.  I'm sure there are reasons for their problems if they knew what to look for.

I don't know exactly why you're having this problem and I can't reproduce it as you can see below.  I tried to follow your steps but it works.  It's a pretty strange process you are working through anyway and I would say totally unsupported, but if you do it right it you should have no problems: