[blocking] Low render distance causes chunks to load very slowly or not at all

Partner Rank: 2
Partner Team Reporting: Everbloom
Verification builds: 1.6 up through new beta 1.8
Summary: Chunks near the player load in extremely slowly when the render distance is 8 or below, or not at all. Player is in "limbo" waiting for chunks for a long amount of time on low render distances. Counterintuitively, lower render distance actually increases wait time for chunks loading.
Impact: In a particular map, players fall through enclosed areas. With high render distance, all is well. With low render distance, the area does not render for several seconds. It's impossible to react to surroundings that you can't see. This is blocking at least 2 maps for release.
Repro Steps:
1. Download and enter the world from slack.
2. Set render distance to something high – 20 or above.
3. Run forward and jump off the dock and observe chunks loading in rather quickly as you fall. Die and respawn as many times as necessary.
4. Set render distance to something low – 8 or below.
5. Jump off the dock again and observe the player stutter as nearby chunks fail to load for much longer than it took before. You will likely die by landing on a block that never rendered. Repeat this as many times as necessary, eventually the respawn will fail due to MCM-333 (caused by low render distance).
6. Additional minor tests can be found in the provided book.
Expected Results: Nearby chunks load in responsively on low or high render distance (naturally, it would make sense for low render distance to finish rendering all chunks even faster).
Observed Results: Low render distance results in frequent stuttering, delays, and missing chunks that are right next to the player.
Screenshots/Videos attached: https://streamable.com/74ik5
Regression Builds: (...)
Notes: I can provide additional worlds for testing upon request.