Why does CALCULATE behave like this when using FILTER?

cliveb2016

This is a lovely question

My article only covers the basics

Also see what happens with

Column = CALCULATE(SUM(Table1[earnings]),Table1)

Actually it has to do with the order in which arguments are evalauted.
Filter Parameter of the Calculate is exected first

Please see this  article

https://www.sqlbi.com/articles/order-of-evaluation-in-calculate-parameters/

So when you introduce Filter(Table1), it introduces an UnFiltered Table in a Calculated Column (ROW CONTEXT). So it has the impact of removing the FILTERS

When you use

Column = CALCULATE(SUM(Table1[earnings]),Table1[Year] = 2011

This is internally transformed by DAX Engine into following formula'

See the article https://www.sqlbi.com/articles/filter-arguments-in-calculate/

Column = CALCULATE(SUM(Table1[earnings]),Filter(all(Table1[Year]),Table1[Year] = 2011))

So this formula retains all other filters except for Table1 Year which you modify to be 2011

Now if you want your second formula to give same results, you would have to use

Column = CALCULATE(SUM(Table1[earnings]),FILTER(RelatedTable(Table1), Table1[Year] = 2011))