Hazel / my rule is processed but with an error

I have a rule with a custom attribute. When the file hits the rule with the custom attribute, the file is not processed in the way it should. When I check the hazel log, I see the following statement:

Caught exception in rule evaluation of file aa7.pdf: [<HazelFileData 0x600003520bb0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key hazelcustomtoken:Rechnungs-Nr.

has anybody an idea what could be wrong? the custom attribute “Rechnungs-Nr.” is just a search on a simple 8digit-number. thank you for your help.

I found the solution. The issue was the for some reason in the “action” part the custom attribute was not readable anymore. I recreated the attribute and the problem was solved.