BEx Query Designer over bpc cube: restrict year attribute of time dimension

Hi gurus:

We are building bex queries on top of bpc cubes (BPC 10.1), but we are facing an issue when trying to restrict "year" attribute of time dimensión (we have transaccional data for 3 years on the bpc cube), at restricting no single value is shown as you can see here:

but If I try to restrict over "monthnum", bex query designer shows me the single values:

what could be wrong?

regards

mah