It looks like when the animation to move the hotbar selector starts, the selector teleports back for some reason. This looks very weird and unsatifying. This issue is exagerated when changing to a slot far from the one you're selecting with the number keys.

This might be cause by the ressoucepack I'm using but it should be fixed anyways. It's also using the same size htobar selector so I don't know why it would do that.

Here is a vid of the issue in action:

Using ImmersiveUI v0.2.2
Fabric 16.5
Minecraft 1.21.1

Other mods and ressourcepacks used:

pastebin

this was happening to me and I'm pretty sure it's because a smooth scrolling mod you have is also trying to smoothen it out, so it visually conflicts

ohhh ok, thanks I didn't know smooth scrolling was doing this kind of animation

in my case, the problem only appeared when I upgraded the version of sodium from 0.6.0 to 0.6.5 for minecraft 1.21.1
Some mods require a newer version of the mod, but the immersive UI conflicts with the new version.
(i have immersive UI does not conflict with the smooth scrolling mod)
P.s. if you change or comment on the line # Affects the speed of the hotbar selector in the config.
"hotbarSelectorSpeed: 3.0" , then absolutely nothing changes .

So does this only happen when smooth scrolling is installed and i just need to turn it off there, or is this an effect this mod alone has?