Update 2022.003.20310 introduced the following change: "Acrobat detects a blank sticky note added and removes it."

There should at minimum be a setting to disable this new behavior.

With this update, sticky notes disappear if nothing is written on them immediately after their creation before clicking somewhere else. This is less intuitive and less flexible than the previous behavior. Simple actions like "add sticky note"-->"copy text to paste into the sticky note" are now made impossible because the sticky note disappears as you copy the text.