When someone puts a Hidden Egg Hunt buff on your Mayor's house, it stops population growth for 12 hours!
I found all the eggs in about 2 minutes, as I'd used a 'Fairy Fire' buff to also find my other collectibles. I have NO eggs on my island, yet still get horrendously penalised with this 12-hours of no settlers!
If you get 2 buffs per day from 'helpful' guild mates, then this makes it impossible to do ANY adventures until the end of the Easter Event, because you can't re-train lost troops (unless you spend bread making settlers in the Provision House).
I thought this bug was fixed on the test server, as stated by BB_Kaurkal here, but that may have been the other issue also mentioned in the thread.