Report studio 10.2 limitations?

[Avisto.sbu]

Hi
I  have to create a chart for which I have following parameters:
X= is a query for X axis
Y= Y1/Y2 is a query for Y axis

not displayed queries
Q1=( Y1/Y2 for year 1)
Q2=(Y1/Y2 for year 2)

evolution between year 1 and year 2 = (whatever calculation between Q1 and Q2) (query for secondary axis)

Report Studio is unable to compute evolution
if I remove this axis the chart displays very well
If I put back the evolution axis I have always this error:

RSV-VAL-0010 Failed to load the report specification. XQE-MDX-0012 The hierarchy already belongs to the projected hierarchy list.

I've already checked that I haven't any syntax or calculation error in all queries

unfortunately there is nothing about this error on google
how to bypass the problem?

//we actually have a mixed model between relational and dimensional in framework manager which doesn't return errors