My guess would be that whopper of a Fidelity setting.
From AI help:
Fidelity can range from 0.5 to 20 pixels; the higher the value, the smoother and less complex the path. Controls the amount of smoothing that Illustrator applies when you use the tool.
I absolutely understand the confusion and why a high Fidelity setting may seem advantageous, but it's not. The way the setting works is counter-intuitive . The higher the Fidelity setting the less Fidelity (adherence) to the original path there is. You should expect more smoothing the higher the Fidelity value.
An easy way to remember is More Fidelity = More Smoothing.
Of course, this depends upon how fast you draw, the scale you draw at, and how detailed you are trying to create paths.
All I see in your videos is the extreme Fidelity being applied when you stop drawing. i.e. path smoothing.
I always set
Fidelity to 1 and
Smoothness to 1%. Smoothness at 0 tends to be a bit too accurate where the small hiccups and twitches are concerned. 1% helps reduce those a bit. Not implying these settings will work for you, merely what I have preferred for years.