I did have a PS4 controller plugged in to my PC using windows10, but I used the keyboard for controls.
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Your PS4 controllers left analog stick might be misaligned and therefore the game registered left input while you were not pressing the A key on your keyboard. So while you weren't touching the horizontal movement keys on the keyboard, it would still register like a -0.1
I will make sure to add a dead zone during the update to prevent this from happening to any other players. Thanks for letting us know about this!