Mineshafts can get cut off at chunk borders

The Bug:

Mineshafts can get cut off at chunk borders.

Occasionally, mineshafts get cut off at chunk borders. However, this can not be consistently reproduced; sometimes, the generated parts don't generate at all.

Previously part of a double-issue bug; MC-214963.

Here is an example:

Seed: -1374521101267461444
Coordinates: /execute in minecraft:overworld run tp @s 1422.42 -30.00 222.01 -137.85 21.90

Steps to Reproduce:

1. Generate a world with the seed provided above and teleport to the given coordinates.
2. Look closely at the generation of the mineshaft.
3. Take note as to whether or not mineshafts can get cut off at chunk borders.

Observed Behavior:

Mineshafts can get cut off at chunk borders.

Expected Behavior:

Mineshafts would not be able to get cut off at chunk borders.