Putting it very, very simply, the data that makes up all those things doesn’t make it through. When the data stream is interrupted or slowed for whatever reason, things like this can happen. The fact that they return just as suddenly indicates something is most likely holding up the flow of information. Remember these are other people’s aircraft. Moving at different speeds, headings, altitudes etc, all in real time. They are constantly being rendered and repositioned. The data moving through the network back and forth is what determines what you see. Or don’t see.
It could also be what’s being sent from the servers, but I have no way of knowing which is which for certain. If everybody was having the same experience at the same time and place, then I’d be thinking it’s the servers, but that doesn’t appear to be related here.