Trial chambers' entrance and atrium connectors sometimes have copper blocks

The following issue seems to only affect entrance and atrium pieces. end pieces connecting to chambers do not have this.

Seed: 1
Coords: /execute in overworld run tp 329 -11 258

Steps to reproduce:

1. Generate a world with the given seed and run the given command

Observed result:

The first image provided shows what it looks like at the connection of the entrance and atrium pieces. As you can see there are two pillars of copper blocks (in the walls).

Expected result:

The second image provided Is what you'd think it should look like, with the usual wall design that's used across the trial chambers.