When dragging the mobile joysticks in any direction, the snap to the edges regardless of how much the user inputs in said direction. This occurs with both the left and right joystick. This also occurs on mobile. I've uploaded a video of the behavior here:
Tested in //UE4/Release-4.26 @ CL 15973114 and the joysticks move smoothly based on player input, so marking as a Regression.
The joysticks snap to the edge upon moving them in any direction
The joysticks would gradually move towards an edge depending on player input
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-126277 in the post.