A lot of your calculated tables already depend on Dates and then you are trying to create a relationship between Dates and ISD(which depends on Calculated Tables that further depend on dates ) so you are creating a loop between Dates and ISD and Calculated Tables. I would say this this is a bad data model since it has so many Calculated Tables based on measures so keeping a track of where something goes wrong is really difficult.
I see you are doing UNION with DAX, you should do this with M instead, once a new column comes into any table you will have a hard time identifying what went wrong.