I'm trying to find a way to interleave filters, so I created a rgb sequence that has 2 exposures per filter in rgb, and tried to run it with "repeat 10 times" in Scheduler. i set dithering every 6, the intention was to have it dither every cycle through the sequence which results in dither every 2 subs per filter. Apparently, it never dithered. Is this expected? In other words, shouldn't the count take sequence repetition and filter changes into account?

I too did something similar recently. It appears, dithering only works within a sequence independently. Also, its frequency must be set to no more than a half of the sequence length or it won't run at all. I ended up with a repeated sequence of 6 shots: RGBRGB and dithering set at every 3 frames. Effectively it dithers every 6 frames once in the middle of each sequence.
The more I use Ekos the more I feel like, for my use scenarios, repetitions should be handled at sequence level, not in scheduler.

I observed that, although if I do a 6-sequence dithering every 5 it does dither, so it appears that it's just enough to dither every less than sequence length, at least for me on latest Stable.