I have recorded this (.mp4) but no idea how to upload it here.

Go to settings > texturepacks

Whenever putting like 2 outdated texture packs on the right side some arrows will dissapear when clicking on them and not work, also when the texture pack is already at the top an arrow-up can still appear, there are many more weird things I have in a small recording.

Whenever clicking save and opening the texturepack GUI again everything is fixed