Why do anims plays weird sometimes? Bug?

Recently the anims in my game started to play real weird, and it only happens sometimes, i wanted to know what happens to avoid that.

The first video shows the normal animation when it plays normal, as it should be. The second is what happens sometimes.

I tried printing what animations are playing, there is no animations playing besides the normal Idle Anim and the ones I do want, so im sure there os no “intruder” track there, and its really weird that only happens sometimes. I’ve even seen this same anim problem with other games I played. How could we deal with it?

This honestly seems like an issue caused by the Animation Engine update, which roblox is implementing lately.
There’s 2 ways to fix this, first is setting up animation priorities properly, which roblox would prefer you to do, and 2nd is disabling the update in workspace’s properties here:

Are you sure no other animations are playing? It seemed like there was an Idle animation playing for a moment there.

When you use:

local Animation = AnimationController:LoadAnimation()

Try to change the animation priority, and see if you encounter the same problem.

Animation.Priority = Enum.AnimationPriority.Action

And as @Zakeksi4ek pointed out, the new AnimationWeightedBlendFix could possibly be to blame, but I haven’t used it myself so I’m not sure.

The defalut Idle anim from roblox characters is aways playing but it seems that it is not responsible for this.
When he is flying there are 5 - 6 animations playing simultaneusly (one for each direction) and its wheights are changed as the character moves, these are at Movement priority. Default idle anim has the Idle or Core priority, so idk.

Worth a shot I suppose? Perhaps there’s also something you missed in your code responsible for the animating which is causing that behaviour, you could try testing it out with some dummy NPCs.