I'm not entirely sure how to describe this and I apologize in advance for the lack of detail in this post but I did make a video showcasing what is happening.
https://youtu.be/mF6TaHXHQo4 (video is still uploading)

As you can see in the video there are strange artifacts in the recording, OBS did not like whatever was happening. (Encoded using GPU)

This seems to only happen in the spawn chunks from what little I have tested. (2 worlds)

Specs:
OS: Windows 10 Pro
CPU: R5 3600xt
GPU: RX 5700xt
Driver version: 21.4.1

Also the water is normal, one of my resource packs updates the water to 1.13 colors. (did not have swamp colors turned on which is required for it to work)

does this also occur on the dev/improved-task-scheduling branch?

Looks like that version of the mod fixed it, although I'm experiencing hitches in the framerate which I would assume is inconsistent frame-timings.

this should be resolved as of the latest commits on master, can you confirm?

Sorry for the late reply, I forgot to test after seeing your reply.

Yes it has been resolved for the most part. The hitches are not nearly as bad as they were but if I'm going to nitpick I'm noticing tiny hitches as I move and look around.

I have a very similar issue with the latest build.

GPU: RX570
CPU: Ryzen 5 3600

Current mods loaded (no particular order):
ForgeRocks-7.7.3-1.12.2
OptiFine_1.12.2_HD_U_G5_MOD
fp2-0.0.1.739-1.12.2
[MixinCompat-1.1-1.12.2]

This has happened when using the Heightmap rendering mode:

And this is what happens when utilizing the voxel render mode:

• When breaking blocks, the following happens:
  https://www.youtube.com/watch?v=RD-pQeBLohc
• • When using the old version intended as a "release" and optifine together, the following happens:
    https://youtu.be/A2H2h30_c-4
• When deleting optifine, the following happens:
  https://www.youtube.com/watch?v=54t-EynP5IM
• • When using the old version intended as a "release" and not having optifine, the following happens:
    https://youtu.be/GA3NBNw1A4I

I am no programmer, but it seems that either FP2 is rendering on top of the vanilla render distance chunks when using optifine, and barely rendering for whatever reason when not using optifine.

The older version seems "more functional" than the current one without optifine, but the holes on the terrain are still many and it, for some reason, seems incompatible with the modlist i'm planning to use, as it causes problems when loading worlds.

For whatever reason, too, the entities dropped on the ground seem to be translucent when using optifine, though I guess that's an optifine problem and has little to do with farplanetwo. Will be testing once I wake up and have time tomorrow (or in about 12-16 hours)

It's 3am and i've pretty much exhausted my options and my brain. Bear in mind I got it to work previously and with mods on top of it on 2022 (downloaded the mod around may-june of that year) and for the previous month or so (before updating all the mods on my modlist including fp2) around the 14th of september. I'm at a loss as for what can be causing such behaviour, since I have played with every setting on fp2, optifine and vanilla mc to make it work again.

Edit: also, sorry for any bad english. I'm slaving away at the moment and trying to assemble any semblance of sanity lol