Naturally generated walls are not connected until the block is updated

What the title says. Only seen it once. The village generated either in 1.16.0.51 or the most recent 1.15 beta.

Updated the wall with the cobblestone block visible in one of the screenshots.

Steps to Reproduce:

1. Create a world using the seed -730362160

2. Run the command /tp @s 158 66 -701

3. Look at the sandstone walls

Observed Results:
The sandstone walls are not connected until they are updated by placing a block next to them.

Expected Results:
The sandstone walls should generate connected.