I've come across an issue using the RegionFunction option in the ListContourPlot function. The issue is illustrated in the attached notebook. I've defined a (concave) boundary mesh region for a set of points and I want to use the boundary mesh to restrict the display of contours such that they only appear within the mesh region. However, the functionality does not seem to be working as I expect it to. I've tried using a different region (i.e. a Disk) to confine the display of contours. And that does work as expected. I'd be most grateful if anyone can spot any issues with what I've done or suggest a workaround. It may also be that I've stumbled upon a bug.

Thanks in anticipation.