My comment on line 375 was too long, so I broke it up into multiple lines. Also I accidentally left a line out of the commit (line 384) when transcribing my changes into the web based editor.
When creating the graticule use the extent from the vectorContext instead of the frameState to determine what parallels and meridians should be created. This will allow the graticule to be drawn correctly on views that wrap across the dateline.
Ryan Curry