Why character walk anim suddenly stops? (Roblox Default Script)

So I am making this game www.roblox.com/games/1454374576/ and if you start walking on any level/PVP match you can notice your walking animation suddenly stops and is fixed just when you actually stop moving. I don't really know what could be the issue, as the script is from Roblox and I am kind lazy to read all that, so I think some of you that had this problem could point the problem to me.

Here are some information about this behaviour or things that I think might be interacting with the animation script:

-I didn't edit/replace the default animation localscript nor add custom controls on the character;

-The animation scripts I made doesn't stop default animations, except one event where when your mount is destroyed, all player animations are stopped, but even before adding this code the bug was happening;

-I replaced the character "Sound" serverscript with a blank one on StarterCharacter;

-Sometimes the character parent is changed to ReplicatedStorage (menu is an example), but not while the player is actually playing;

-The camera becomes scriptable while playing and is updated with renderstepped.