I know this bug, I had to correct it on my mac for v5.8. It was probably working for you before because you were using a patch I had proposed (taken from vtk master): https://gist.github.com/ocommowi/7545348

Or is it because you switched from release-5.10 to v5.10.1 that the bug appeared (is there any reason for one or the other by the way) ?