When loading up a world or joining a server with RTX off then press colon ';' to turn on RTX, the PBR textures will fail to load properly. This only happens after the game is first loaded, and if RTX is turned off when joining.

Steps to reproduce:

• Make sure you have an RTX-enabled pack installed and meet the system requirements for RTX in bedrock...
• Go into the settings and make sure RTX is Off 
• Restart the game
• Find yourself a server to join, a friend to connect to, or a singleplayer world
• Join the world
• Press ';'
• Watch as the PBR textures fail to load

RTX pack used in testing: Radiant Pack RTX by Lioncat6