There are cases when the Launcher does not save selected game version for an installation (aka profile)
when the setting "Keep the launcher open while games are running" is turned OFF.
Despite my long and detailed description, the case is simple and really happens in normal usage of the launcher.

Short description:
After a game version is changed for an installation, the user may immediately go to "Play" tab and just there press "Play" button. The launcher runs the game, closes itself, but the selected game version number is not being stored for the installation. Next time the launcher starts, it shows the previous version (before the change), as if the user would not change the game version at all.
Whats more, if the user does not notice that the game version on the list is not the one last time changed, he may run immediately the game with improper version, risking unintentional corruption of his worlds.

Steps to reproduce:
1. Create a new installation and assign any available game version to it (I tested "Release" versions only).
2. Just after pressing "Save", while being on the "Tnstallations" tab, press "Play" button, so that the installation runs once and the launcher closes itself. Then, exit the game.
3. Run the launcher again. On the "Play" tab the new installation is selected with the previously selected version, which is OK. Do not press "Play" button, but go to "Tnstallations" tab to change the game version for the installation.
4. Find the installation on the list, go to its Details and choose any other game version. Just after pressing "Save" DO NOT press "Play" button, but immediately go to "Play" tab, see the changed game version is OK and just there press "Play" button. The game runs OK with the changed version and the launcher closes up. Then, exit the game.
5. Run the launcher again. On the "Play" tab you can see the wrong game version - not the recently changed one, but the previous one, before the change. And this wrong game version is really used for the game after pressing "Play" button on the "Play" tab.