Signs go blank with text and date

Description:

Sign go blank when inputting a text with date.

This can happen with any text and other characters but I found it happens more when using a date format like 13/06/2021.

Steps to reproduce:

1. Place sign
2. Write text
3. Write a date/ any numbers
4. Exit the sign

What should happen:

Sign displays inputted text.

What happens:

Sign shows blank, not 100% chance.