Why Does Custom Function in Name Get Called Twice?

This is explained here
Excel first tries to calculate named ranges. The first attempt to calculate TestRef fails because the R parameter is Dirty. TestRef is scheduled for re=calculation after the input parameter has been calculated. The sheet is then calculated and then TestRef is calculated again. So TestInfo is hit twice.

This one is only hit once...

Function TestNothing() As String
    MsgBox "TestNothing "
End Function