Pretty sure the minus symbol - in the measure name [M-Month] trips the formula in your next measure. Try removing the minus in the name and in the formula to leave it like MMonth and see what happenes. - is a substractor operator and any formula operators shall be avoided in the names.
Edit: If you want to use hyphen in the name, you can use the designated hyphen symbol –. On Windows it can be inserted by holding [Alt] and pressing numbers 0150.
I did what you suggested and it broke the skin.
Statistics: Posted by HardNeck — Today, 3:24 pm