Update:
you can reproduce it while holding a movement button, fast!! turn the mouse to the left/right and then back to the center while you stop pressing the buttons, and you will be stuck in your movement animation

update2:
shaking your mouse like a circle while stopping from moving also reproduce this

iam no expert but it looks like it dont go into the stopping animation and will continue to play the walking animation...
still testing to abort the stopping with other things like going over sidewalk end, no clear results yet :/

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I can reproduce the problem if i press two movement buttons (like w & a) and then make a fast turn with the mouse

https://www.youtube.com/watch?v=dIEAOo_IWMM[/outdated]