Problem with ATP Check in Material Master

Hello

I have been searching for a solution - but this issue make me speachless..

What i did?: I configured for different Materialtypes different required fields in the system (OMSR).

Now i got the issue that the entry in Availability Check in Sales: Gen/Plant and the Availability Check in MRP 3 disappears when i select an another tab! I mean i select an entry and go to an another tab till MRP 3 and what i see is that my entry is gone.

I customized fixed values in Customizing for the ATP Check for plant and Material type, but no chance the entry does not appears in the Material.

Does anybody has an idea to solve this problem?

Thank you very much!!