Why am I getting a MDXSCRIPT Model Error - DATEADD PowerBI when I am using my Calendar Table?

I am currently working on building a model representing YOY and MOM for Net Revenue. Everything works for YOY - MOM I am having issues.

My MOM works fine; however, the table is showing days and I just want to see Months, not every day in the month.

I do have a Calendar Table:

My Dax is referencing the Calendar Table. When I change my MOM to reflect Months instead of day, I get this error:

I am not sure what is happening?

I have tried leverage both Date and Month and seems to work in the model, but i don't want 'Date' in the model because it brings in all the days.