We're looking into this, but in the meantime. there are a few things to try here.
The first step would be to make sure to update your video card drivers.
The next step would be to make sure that there are no issues with the installation of the game.
You can do this by opening the game and on the main screen, going to settings > troubleshooting > then hit the button to 'force game data reinstallation'. Or if you're on Steam, go to the Steam client, then right click on OOTP 24 and go to 'properties' > 'local files' > 'verify integrity of game files'.
If those steps still don't work and you see the disappearing players again, then try playing in '3d modern mode', if you've been playing in '3d classic', as the classic mode is where this seems to sometimes happen as of now.
Finally, if you still see this, please turn on debug mode as per the instructions in the link below and send us the resulting trace file from the game up to the point where the players start disappearing (before you close out or restart the game). Thanks!
https://support.ootpdevelopments.com...P%20debug%20(5).