Sign text doesn't show with RTX on

While playing in a world with RTX on, I noticed that all the signs were empty. Then, I turned RTX off and I could see all the text in them. I'm using Vanilla RTX Normals.

This started happening in 1.19.70.24 Preview.

I think this is related to MCPE-167551.

Steps to Reproduce:

1. Write something in a sign.
2. Turn RTX on.

Observed Results:
The sign text isn't visible with RTX on.

Expected Results:
The sign text is visible with RTX on.