This is to help fix people having issues with dialog cutting out or overlapping. The issue normally is with people with higher hz screens like 144 and above. I found a variety of solutions to this without having to sacrifice your monitor.

Bring up the NVIDIA control panel
Go to manage 3D settings
Scroll down to vertical sync
Set it to "Adaptive (half refresh rate)"

If you have a 144hz monitor that should lock it at 72 fps. Fallout 4 is locked at 60 fps. Why? No idea other than bethesta cutting corners. They really need to bug fix this.

Another solution to this is disabling vsync
Open NVIDIA control panel app
Click manage 3D settings
Select vertical sync
Chose to either enable or disable

Fully disabling can help sometimes, it worked on an old monitor of mine that was around 144hz and below. I currently have one that runs much higher as to why i set it to adaptive. Which fixed the dialog bug for me.

Just a few random fixes that might help:
-Get latest drivers (updating if needed)
-Remove mods
-Resetting your games
-Running in borderlines window
-Locking the FPS

If none of these work, it might also be the tripple buffer.
To fix that:
Open NVIDIA
Choose system settings
3D settings
Add Fallout.exe to programs
Change "Tripple Buffer" to on

If you have any other issues you can leave a comment and I will try to get back to you and help out best I can.