On serveral occasions in the last few days I have clicked on a building and got the pop-up window for another building.

Although I have thought it was odd to get the wrong pop-up, I dismissed it because I have usually just been moving my position on my island (click & drag).....thinking it may have been a lag issue.

However just now I arrived on an adventure ( Bandit Nest ) and clicked the quest icon expecting to see the quests associated with the adventure, like how many collectables I need to find.....But instead of the quest list my mail box pop-up appeared!!!...don't think that was just lag.

These odd pop-up are quite random...havn't found any connection yet (apart from lag), but I'll update this post if I do manage to figure out any possible cause.