Pattern Parse Error: f[x:(_..)]

[rocky]

From https://github.com/mathics/Mathics/issues/668

foxy-sheep -e 'f[x:(_..)]'
line 1:8 no viable alternative at input 'f[x:(_..)'

[rljacobson]

Is this a version of the ambiguity between x_. and x_..? Mathematica (the software) treats the expression x_.. inconsistently between the Notebook and command line interfaces. See here.

I consider it a bug, though. Like #3, it is one of the many edge cases involving .