Put the summary of the bug you're having here

What I expected to happen was...:

I would load up the game to play for hours and hours.
What actually happened was...:
When I got to the main menu the screen seemed to have bugged to the point where it would zoom in too much and then it would go to the bottom

Steps to Reproduce:
1.  While in-game set to fullscreen off

2. Close Minecraft

3. Open the launcher and make sure it is on 1.12.2

4.Launch the game

5.While in-game set to full screen 

6. Maybe the inventory, settings, etc. will be in the bottom right and zoomed in

 
Extra
 While I was taking screenshots I wanted to make a recording and give examples(Note I was in full screen and it was bugging out). When I checked the recording I noticed it was fine.

Also, when not in fullscreen, everything is how it should be.