How can I get ambiguity with only unidirectional relationships?

[eilmrein]

I have the model shown here

Why can I not make the relationship between cuve v_FiscalAccount and PnLPosting active? All relationships are unidirectional...

[HotChilli]

There would be 2 paths from cube v_tenant to PnL Postings

[eilmrein]

So what? If I filter on cube v_Tenant, there is no ambiguity, as all tables that ultimately filter PnL Postings get filtered and I'd expect cube PnL Postings to be filtered with all the filtered items to be used as a compound filter context.
Here's the same thing, in a more complex way, that actually works! (Think of cube v_FiscalPosting, cube v_FiscalPostingDocument and cube v_FiscalPostingToPnlNode as the combination the former PnL Postings)
Filtering on cube v_Tenant ultimately also results in muliple filter paths applied to cube v_FiscalPosting.

However, when I deactivate the relation between cube v_Company and cube v_CompanyPnL and try to activate the relation between cube v_Tenant and cube v_PnL instead, I get the same complaint about ambiguity...