[MC-158015] FPS drop when entering a specific chunk

When entering some specific chunks, the FPS suddenly drops to 0 for a short moment.

It doesn't affect every chunk, and it happens every time we enter them with a specific direction (for some it's while looking east, other north, other both...).

Here's the content of my latest.log:

[23:43:23] [main/WARN]: Something's taking too long! 'root.gameRenderer.level.terrain_setup' took aprox 331.8086 ms
[23:43:23] [main/WARN]: Something's taking too long! 'root.gameRenderer.level' took aprox 335.5714 ms
[23:43:23] [main/WARN]: Something's taking too long! 'root.gameRenderer' took aprox 336.711699 ms
[23:43:23] [main/WARN]: Something's taking too long! 'root' took aprox 339.5396 ms