Tall seagrass only generates lower part when ocean monument is in the way

Can confirm in 20w49a.

Can confirm in 21w03a.

Can confirm in 21w06a.

Can confirm in 1.17.1.

Can confirm this in 21w40a.

Can confirm this in 1.18 Pre-release 4.

Here are some extra details regarding this problem.

The Bug:

Tall seagrass only generates its lower half when ocean monuments generate above them.

Steps to Reproduce:

• Generate a world with the following seed and teleport to the following coordinates.

Version: 1.18 Pre-release 4
Seed: 2671478887814226195
Coordinates: /execute in minecraft:overworld run tp @s 18670.72 36.35 723.29 572.46 -6.92

• Take note as to whether or not tall seagrass only generates its lower half when ocean monuments generate above them.

Observed Behavior:

Tall seagrass only generates its lower half when ocean monuments generate above them.

Expected Behavior:

Tall seagrass would not only generate its lower half when ocean monuments generate above them. Instead, they should not generate at all to avoid this issue from occurring.