Launcher changes screen resolution whenever it is opened

Whenever I try to launch Minecraft, my main monitor's resolution will go from 1920 x 1080 to 640 x 480. Please note that this isn't an issue with the game itself, after it has started: I am able to play it, albeit it also launches on a lower resolution and on windowed mode.

This wouldn't be an issue if the launcher didn't change the whole monitor's resolution, which leads to difficulty controlling everything, as well as making me rely on my secondary monitor for help to turn things back to normal. 

This is how the whole screen looks like:

A view from Windows Control Panel:

How it should look: 

I have scoured every setting — both in-game and on Windows — that could help me fix the issue, but it only happens in Minecraft. What is causing and how can I fix this issue?