Yesterday morning there was a racket from Lotti, which I guessed (correctly) was her distress that she wasn't being allowed in the nest box.
I opened the egg port to find Florence occupying one nest box. Her beak was covered in egg, and at her feet were 3 eggs. Or rather, one unharmed egg covered in egg yolk splatter, one egg with a peck mark in the shell, and the remains of third.
I imagine that the first egg could have smashed accidentally, but the peck mark on the second egg was worrying. Maybe Florence hit it by accident when attempting to eat the eggy mess from the smashed egg?
I hoiked her out of the nestbox anyway, and cleaned up the mess so that Lotti could lay.
We will have to keep a close eye on this to see if it was a one-off or not.