Make sure you have the latest version of Joiplay and the RPG maker MV plug-in for it. Google also gave this instruction for a fix, I'm not sure if it'll fix your errors. I don't handle Joiplay things, so I don't know why it doesn't work. ->
Open your JoiPlay app.
Find the game showing the opacity error.
Hold down on the game icon until a settings menu pops up.
Tap on Optimize Map.
Follow the on-screen instructions to finish the process.
