...just what the title says, basically. If you partially mine a Limpet Rock, so that it visually updates and looks broken, and then relog, it will appear as if it was never mined at all. If you hit it after that relog, it'll update again, but that will still be lost if you relog again.
Steps to Reproduce
Mine a Limpet Rock until it visually updates, then relog.
This issue has not been confirmed by a developer yet.