Bare in mind, we are looking at tiny...tiny discrepencies in the timing.
In your first example, beat error 0.7ms look at the width of the gap between the lines and this is just 0.7ms
By the time you get to 0.0ms the lines start looking like a single line.
If you look closely at the 2 0.0ms examples you can just make out a tiny rise and fall in the lines. There is 2 lines there but they are so close together they appear as one.
Regarding the loss of time on the first example when the lines are moving down, the loss is so small it is not registering.
With the other 2 examples they have been on the machine for 4 seconds. If this had been read after a greater time period you would see the lines dropping off very slowly.
Hows that sound?