I am getting strange artifacts when I export to .gif, .png sequence, and video. its little ghost bits of a moving shape (see the right edge of the green hexagon).
Any way to fix this?
That's odd -- We sometimes see this as a part of the conversion process. Can you try enlarging the purple background from 100% to 101% during the animation? Or increasing the framerate by 1 fps?
I increased the size of the background and also tried changing fps from 15 to 24, artifacts are still there.
You may want to try using the older GIF export engine, which is explained here: GIF export never finishes - Using Older GIF Export Engine - #2 by jonathan
(Also happy to take a look at your document)
I've had this before, not just exporting but when previewing with a browser. I think it has to do with a layer being too big dimension wise and when animating its width and height constrained from large to small (not scaling it) causes some rendering abnormalities maybe. In that case, I'd recommend making sure the layer that hexagon looking shape to be imported at just the right size.
A workaround is exporting a MOV file and importing that into Photoshop. Then export it from there as an animated GIF using the pretty good GIF encoder they ship.