​ATC-Check for S/4HANA Field Length Extension Material Number - only finde SOME(not all) cases?!

I use the ATC-cheks for S/4HANA: Field length extensions - Material Number to find necessary adoptions in my code.

Here I notice something strange: One line is found and marked as problematic, good. But a few lines above, exactly the same thing is happening: a 40-char filed is pushed into a 18-char fiel (which is not a good Idea!).

And it's not marked at all. How come? And how can I gain trust in ATC-checks, if they miss such things? :-(

System: S/4HANA 1909 (initial shipment stack, S4CORE 104 0000; SAP_BASIS 754 0000).