Name: greene Savannah, GA (Sunset 28) (Zone 8b) I have no use for internet bullies!
Not knowing what type of maggots they are I can make a guess. It only takes one day for the common housefly egg to hatch into a maggot so I would think the fly deposited the eggs onto your soil and less likely that the eggs were leftover from the compost process.
You could try to repeat the experiment by re-planting in a controlled fly-free environment and keep the planters in a screened enclosure.
Sunset Zone 28, AHS Heat Zone 9, USDA zone 8b~"Leaf of Faith"
