The bug
Same as MC-148009 but this time for 1.14.1 Pre-Release 1
When returning to the main menu, clicking on "Minecraft Realms" button, creating a new world or starting the game the following error appear in the log:
Failed to load Realms module: Realms incompatible. Built for Minecraft version 1.14, trying to load in 1.14.1 Pre-Release 1. Note that the realms plugin isn't forwards compatible any longer.
I don't get that error on 1.14.1. Are you sure it affects that version?