Greater Stealth Totem stacking bug [GAMEPLAY]

My was on cooldown and I upgraded to and the cooldown reset again like normal. After a full minute I expected to have a ward stack, but did not. It gained 1 stack but the icon on my HUD was still dim and I could not place the ward. After another minute, I should have had two stacks but instead got my first placeable stack.

Not sure how to reproduce, but I was playing Sivir when it happened.