Please give the steps taken to trigger this, or provide a save game file. I would like to replicate this bug.
Wait? Version 0.2111? Oh, they released a patch just now?
Ohhh, this reminds me of a certain cavern related bug...
Food that appeared in caverns would be marked as buried.
Anyway, just playing the level and killing the woodlice replicates this.
They are visible on the map as food items.
Notice how only the coach horse beetle that died in the cavern they spawned from is unharvestable.
This looks so similar to the cavern bug, where food dropped in excavated caverns thought it was still buried.
Right this will be part of a change made in the most recent patch, may need to re think how it works. A change was made to optimise the burred check for dead creatures, clearly it has had some unintended effects!