Mausoleum tooltip bug?

[japanesesamurai]

”must be adjacent to a harbor built by this city”, the tooltip reads.
However, in my capital, I can build this wonder adjacent to a harbor built by another city as well.
Is this a tooltip error? Or a game error?
In the manual it is different: “Must be adjacent to a harbor district.”

 

[AlannaT]

Does your capital have an own harbor, too? Because I believe for wonder placement there are two (or more) independent checks, in this case: a) Is the spot adjacent to a harbor? b) Does this city have a harbor?

 

[japanesesamurai]

No, Istanbul doesnt have a harbor.
I guess the tooltip is wrong as it is correct in the civilopedia: “must be adjacent to a harbor” ... which means any harbor