I'll place a sign, and write something. Once I leave the sign the words flash and then disappear. Same issue with book and quills. This is only an issue for realms as when I'm playing solo I haven't encountered it.

I've attempted to redownload the world onto the realm, multiple times and this has not fixed the issue.

I play Minecraft Bedrock on my windows 10 pc with friends who play on xbox/phones etc.