(Pro 3.0.2) Last year I made a custom arcade expression for my symbology:

worked fine and it still does.
Yesterday I joined the feature with an excel table, shows up as expected after import symbology.
I copied that joined table 'feature class to feature class' to have a permanent feature including the joined data and imported the symbology once again but I can't get it to work: nothing shows in my map.
After the original imported expression didn't work I tried this (following set-custom-expressions-for-symbology 😞

but nothing visible in the map, after some time this shows up in the symbology pane:

what am I missing here?
Solved:
After more errors like the one above:

I manually re-created the expression:

which renders perfectly now, I fail to see the difference, no idea what actually happened
Have a nice day!
Bert