Error when generating a result

[[Da...]]

Good morning, colleagues,
I get the following error when running the report; however, if I go into the characteristic itself, the value does appear.
What could be causing this?

 

 

 

 

 

Edited October 6

[[Jo...]]

I have found that deleting and recreating the characteristic can help with this sort of error

[[Da...]]

The Zeiss Error are great at giving no information of what is wrong 

 

[[Ri...]]

Dictionary>>keyNotFoundErrorFor:Index:

Makes me think of a pattern.

Is the feature using a pattern? 

Is the characteristic calling from a pattern?