I am using SQL server 2014 and I have a number of tables with foreign keys where they are set as untrusted. NONE of these FK as set as "NOT FOR REPLICATION" and the command seems to run OK.

I have  tried dropping the FK and re-creating and it creates ok but is always marked as is_not_trusted = 1
I have even tried creating a new column of the same datatype and creating a new FK (to the same table) and the same thing happens.
The FK MAster table looks ok.
this does not happen to ALL FK just a few (13) out many that exist.

Any ideas?