I have seen this bug before as early as I first noticed it in 1.20, though it may have started earlier since 1.20 was when I started testing it. When at or above +/- 8388608, some inlet caves seem to generate unusual and seem to be more “blocky”, like a precision of two blocks. This only affects smaller inlet caves and not large chasms. I have found this on many seeds.

I have attached below some screenshots of what I mean. I have not noticed this bug below the 8 million floating point.

I also have recently found this same occurrence in lower near-bedrock “spaghetti” caves.
Steps to reproduce:

1. Create a new creative world with the following seed:

   7306644533854031802

2. Run the following command:

   /tp 8388195 10 8388644

Expected result:
Caves after 8388608 on x and z axis should look like normal caves.

Observed reults:
Caves after 8388608 on x and z axis look weird.