The bug
If you click on a player while in spectator mode to view them in first person, the game will not render any more chunks.
How to reproduce
Click on a player in spectator mode
Have that player walk out of your rendered chunks
Nothing else will render until you "leave" the player
This appears to be a duplicate of MC-148993, which hasn't yet been resolved. If you have any additional information to provide regarding this issue, feel free to comment on the parent ticket. If you feel that this issue is affecting you, feel free to vote for the duplicated ticket, to give Mojang a basic idea of how many people are impacted by the problem. Just to further inform you, this will not determine how quickly the bug gets handled or fixed.