The Chroma crosshair disappears for some reason if you set these settings:

Scale: 1
Framerate: 30
Frame Count: 60

For some reason, if the frame count is above ~15 some frames become invisible as if the rainbow isn't properly looped.

There are only 15 frames in the CHROMA_PLUS crosshair:
chroma_plus.png
Therefore extending the frame count beyond the total frames in the image file will result in the mod trying to render frames that are empty. In the future might modify CHROMA_PLUS to have 180 frames so you can slow it down while still maintaining a smooth framerate, but for now this is not considered a bug.