Like @TheQuin said, it seems this has happened before.
Please pm me your user id's for those users who have halved rewards. Also please mention how you are using the website in your message - mobile app or browser and version of the browser.
I haven't been around long enough to know if this is a yearly spotcheck of some sort. My guess is that if you have sent them a message and they think you are not abusing the faucet they will whitelist your IP, just as someone reported earlier. Or their system will eventually sort out, by way only they know, if you are or are not abusing the faucet - my guess is that it is based on a combination of your activities, free rolls, deposits, multiply, lottery ticket purchase; your behaviour while using the site.
If that is the case I think the best way is, if you have sent them a message, to wait and play free rolls or multiply or what ever you usually do and let the system have data of your activities.
But of course I might be wrong

. I offer my opinion without expertise.