Illustrator CC Rectangular Grid Tool forces skew = -500%
I haven't used the Rectangular Grid Tool in a while, but now I need to and I'm finding that the horizontal dividers skew is refusing to stay set to zero. I open the Rectangular Grid Tool Options, set the number of dividers, set the skews to zero, click OK, draw my grid, and the divisions come out non-linear, as shown below. When I look back at the options, the horizontal divider skew has reset to -500% or something of that order of magnitude. No matter what I do I can't seem to make Illustrator generate a regular grid. Really annoying.
Any suggestions appreciated.

