Possible corrupted Graph in database version

I think one of my Graphs is corrupted. In the Graph view when I try to filter by Tags, no tags are shown.

On the Demo graph and any new testing graph I created to test, it works.

I tried the Validate Current Graph command, but it found no errors. Unfortunately it’s the one Graph that I already did some work, and it’s not easy to start again.

How can I fix this?