Why does Powerbi not correctly aggregate whole numbers correctly from another table?

I am wondering why Powerbi doesn't Sum/Min/Max a whole number correctly from another table

This is just a rudimentary example, but let's say I have 3 tables as an example. I have a fact table, a many to many dimension table (and I want the dimension table to filter the fact table) and a One to Many Dimension Table, with the dimension table filtering the fact table

In Powerbi, I can bring over all of the data in my fact table, and then when I bring over a whole number, let's say the Calls Made, it doesn't know what to do with them

But when I bring over a column from the Calls Made Table, it works

This also happens in the One to Many Table as well, so I know it isn't something with the relationship. I know that if the Many to Many has Both Cross filter direction, it works properly, but I don't want that. 

I've been able to work around it using the TREATAS(VALUES), but I am just curious if there was something else I could do?