Unable to add more than 2 parents for child when "tier descriptions processing option" is enabled in

Unable to add more than 2 parents for child when "tier descriptions processing option" is enabled in P0150 even though effective dates are not overlapped. Where as disabling the same able to add .

Even though eff dates are not overlapped when i try to add a parent to a particular child P0105 is throwing "Multiple parents exists". I notices this happening when a child got already 2 parents attached but with out overlap of eff dates.

I am able to attach the parent if i delete any one of the existing 2 parents links.

Is this a standard function of JDE?

Please suggest how to fix this and what could be the root cause. Below are the screen shots for reference.