When you throw an ender pearl and pause the game before the cooldown is up, you might notice the bar showing the cooldown glitching up and down. This is a minor bug and only affects single player as far as I know. To replicate, create a single player world, throw an ender pearl, and pause the game at the same time as in the image shown. You should see the cooldown bar going up and down.
Linked issues
Attachments
Comments 1

Duplicate of MC-166809