I've analyzed everything I could and there's nothing wrong, neither in your map nor in the script command of the "parallel" event.
The following video shows your map working without any intervention from me:
(The RMMZ and game menus are not in English because I don't know how to do that in this engine, only in RMMV)
I tested it with all available versions of RPG_CORE, from 1.0.0 to 1.3.3 which is the most current.
My advice is, uninstall RMMZ completely.
If purchased at the Delgica store, consult the manual or support for license maintenance.
If using Steam, use the manager.
In both cases, I advise to delete the RMMZ folder completely after uninstallation.
Restart your computer and reinstall RMMZ again, as none of the projects ran files, you won't need to create new ones.
But if so, use the menu to update the test project's CORE, as shown here:
Hello RPG Makers! The latest update, Version 1.3.3 is live! Thank you for using RPG Maker MZ. As always, we appreciate your support! We hope you are enjoying it so far. Download Link Bug Fixes Fixed image errors in tileset. Outside_A1: "Poison Swamp" and "Dead Tree" have a noticeable joint...
I believe that I don't have any other method to be able to help you. So I wish you good luck.
I have no idea why this would be the case, but after loading up the project again, it suddenly works.
And not only that! I realised that the function doesn't actually reset, so you don't need a parallel process, you just set the new focus once and then reset it later. That's awesome!
The only problem is that I don't know how to focus on the player again. Could you help me out one more time, Dev_With_Coffee? Or anyone else?
Micro rant. The worst part of working from home when you live with your family is seeing how inconsiderate they are. "Hey, you're sitting in front of your computer, that means you're not doing anything! I want to put the TV at 200 decibels!"
If I was working in the office would you still talking me like that?
It's definitely discouraging when streamers give a try-to-say-it-nicely (i.e. bad) review of your game demo. It's like jumping into a cold pool. Bad initally, but it gets better with time. And you are now more alert and see better.