I’m seeing the same thing if I don’t specify all required parameters to match one of the methods. It feels like the error reported is different, but it is definitely an error. I haven’t bothered going back versions to see what it was though.
There is a bug in 2014r3 where the compiler mistakenly considers ByRef as a conversion in some circumstances, which can lead to incorrect errors about ambiguity. It may be related to what you’re seeing.