Tags not visible on one Mac, visible on the other

I have a strange issue. I use Logseq on a MacBook and iMac with Logseq sync. On the Macbook Logseq works perfect, on the other iMac the tags are not visible. When I hover over the tag, the tags are visible again. When adding a new tag #test, it is also hidden.

I re-installed Logseq completely on the iMac but still the same issue. How can I see the tags again on my iMac too? Thanks for your suggestions.