The bug
This happened twice to me today.
After leaving a nether portal to a swamp, the swamp colors seem to be incorrect on some blocks. They change to the correct color after a block has been updated.
This issue also happened to @unknown, but with the ocean biome colors; see MC-174157. With "Biome blend" set to default, my issue looks very similar to it.
Video
Started recording after having left the portal:
[media]Related issues
is duplicated by
Attachments
Comments


This might be related to MC-166123

confirmed - 20w12a

In 1.16.1 and 1.16.2 Pre-1
Can confirm in 20w51a.
Can confirm in 21w03a.

The version number of your world generation has no effect from what I can tell. Generated a world in 21w06a and it had this happen. Also I have never seen it happen except after exiting a nether portal, so I don't think it happens when chunks load normally.

Can confirm in 21w39a. Isn't this the same bug as MC-166123?

Can confirm in 21w40a.

Can confirm in 1.18 Pre-release 2.
Can confirm in 22w03a.
Can confirm in 1.18.2.
Can confirm in 22w12a.
[media]Can confirm in 1.19.
Still in the 23w17a?

Can confirm for 1.21.3