Looking at the screenshot again, could it be possible that you have placed a beacon plot in the same location where the Campfire used to be? Currently, you cannot add plots to a Campfire as shown.
But if you add a Beacon Control block to it, then you can get the green highlight.
Then by removing the blocks, it creates a situation similar to yours.
So if you used the Beacon Plot Remove Tool, you can reclaim those plots. Could you check if that's the case?