Validate metadata issue in FCCS (Revenue acc under Net Income, shared member with subtraction value)

Difficulties in creating an Reversal account under FCCS_Total Pre Tax Income node.

We have create an Special_Items account for Net Income under "FCCS_Total Pre Tax Income" node, then now we are trying to create an Special_Items_Reversal account under the same parent account to zero out the Special_Items impact from "FCCS_Net Income"

In the 1st approach we created the Special_Items_Reversal as dynamic calc with the formula: - Special_Items; After deploy and consolidates the cube we are seeing the expected values under Net Income, however, it is showing an issue in the validate metadata feature.