Here is the example: Cesium Sandcastle
Description: As in the example, the polygon GroundPrimitive in 2D mode could render in high zoom level, but some parts of it disappear in lower zoom level.
In high zoom level:
In low zoom level:
It’s not unlikely that this is related to the polygon crossing the antimeridian. At least, it looks like that, when interacting and zooming in. But details still have to be investigated.
Here’s a sandcastle where the polygon doesn’t cross the anti meridian. If you zoom out, the issue still occurs.
Will do brief investigation to see if I can find the bug, otherwise we can make an issue (or mention on a similar issue, like this one)
Could be related to this issue: