After the update, the inscription on the tablet disappeared on the pre-created world. The lettering on the plaque was white using luminous ink.

To reproduce:

1. Create new world with Experimental settings on Minecraft version 1.17.30.21,
2. Write something on the sign
3. Painting the inscription with some color
4. Use glowing ink
5. Enter the world created on version 1.17.30.21 on Minecraft version 1.17.30.23

Observed results:
The inscription is gone

Expected results:
The inscription must be preserved

Seed: -477156033
World setting in screenshots.