Hello :)
Make sure your new idle assets for the skin is actually visible (not empty frame).
And make sure the Origin and Center points are at the bottom center of the skin (double-click on the skin object → points editor).
If your new assets canvas size is not (32x32) as the original asset, then you need to adjust the skin position event (Game scene events → Player mechanics → Skin + horizontal flip → Change PlayerCollisionBox.Y()+32 )