[Designer] Moving a single vertex in face mode moves the wrong vertex.

[Vhwatgoes]

Grabbing a single vertex in face mode may select and move a different vertex or many additional vertices.

 Video Example

In this demonstration, the design is sitting at 65% of the allowed data limit as I attempt to adjust some vertices. Notice the response times before a change is finally made to a vertex.

I select a Vertex, drag to move it, and one of 3 things happens:

1. The vertex I selected is moved normally.
   
2. The vertex I selected moves, but several new vertices are now selected too.
   
3. The vertex I selected does not move, instead several other random vertices move in the same direction and distance I tried to move the single vertex.
   

I seem to reliably get a grip on the program when I select a few other vertices to kind of 'reset' my selection. After that I have a good chance I will get the intended result. Not sure if this actually does anything but it's become my ritual.

The more vertices I move without doing this, the higher chances an error seems to occur, with more errors each time.

[Deantwo]

Lock or hide objects you don't want to move?
Or do you mean moving corners in face mode?

[Vhwatgoes]

Lock or hide objects you don't want to move?
Or do you mean moving corners in face mode?

I selected a single part with 1,757 faces, and you can't lock individual vertices for just face mode.

Vertices = Corners

It's not really like clicking on something but selecting something else behind it, or a case of selecting things directly behind me. I am unintentionally moving corners that are sometimes in the region of what I am trying to move, or sometimes on the other side of my screen. It is very random.