'App' is damaged and cannot be opened. Delete 'app' and download it again from the App Store

I was trying to download some apps on my MBP. I tried downloading three different apps . All of them completed downloading successfully but when I tried to open them they failed and I recieved a popup saying that ' The '**** app ' is damaged and can't be opened. Delete the '**** app' and try downloading again from the Mac App store.' . I believe this has nothing to do with gatekeeper ( I've set it to 'anywhere' anyway).