Ambiguous path in Direct Query copy of dataset, not in original dataset

[aJayMitchell]

Hi all,

I've just started receiving the following error in a Composite model that I have. The model uses two datasets (Finance and Manhours) as it's source, and links these two datasets together via a common 'Jobs' table.

To rule out any issues within the Composite model itself, the first thing I've done is to remove the relationships between the two dataset - so the model is now basically just two DirectQuery links to separate datasets.

I completely understand what the error is trying to say, but I simply don't believe that any ambigious paths exist - and that's confirmed within the 'Finance' dataset where no error is shown (the two tables named come from that dataset). 

There are no additional relationships added in the composite model - so the only relationship are those which exists already in the Finance model.

Any ideas?!

[aJayMitchell]

To better show the underlying model where the issue lies - this is a simplified version which still has the error:

Now I could understand that if the highlighted relationship was active, there'd be an ambigious path. But it's not. So why is it giving me this error?