When changing the resolution of a resourcepack and backing back to the title screen, most of the time the textures don't update until the game is restarted.
I've tested this on windows 10/11 and iOS 15 and it happened in all of these versions

Steps to reproduce:

• Download and install the pack
• Apply it in global resources
• Go back to the main menu
• Change the pack resolution in global resources
• Notice the textures won't update until the game is restarted