Not with Kaleido, it's a normal monochrome eink screen underneath. The color filter on top changes in something like 1ms, it's invisibly fast. ACeP and the other black/white/(red|yellow) "color" inks do require multiple cycles though, and yeah - wildly unusable for reading purposes.
I have a Pocketbook Colour which uses E Ink Kaleido and it takes multiple refreshes to correctly display colours - there's 3 or 4 flashes on the coloured areas.
Go to about 3:57 on this video and watch the book covers flash on and off as they do multiple refreshes - easier at 0.25x but still visible in real time.
