I've lost a rare grafiti G-00066:DE:E somehow.
Unfortunately I don't know exactly when and how.
It was last seen at 22.06 on steam and most likely lost during transfer back to my screeps account at 22.06.
In the steam history can be seen that I took the sell offer back. I've never converted any grafiti item back to 400 pixel resources, so it had been lost in transfer.