I see the same here, moving the camera doesn’t fix it (or… rarely).
It seems it is related to some sort of “bounding box” and limited to a “band” in Y screen coordinate.
Creating some object to have a bigger camera bounding box gives a wider band in Y screen coordinates where the marker is visible: (just a dumb guess by an ignorant fool)
Now WIP makes my GPU do coil whine while the marker is visible… lol