USCIS Started Cashing checks of H1B Petitions FY quota 2018. The first report of cashing the check by USCIS is reported in afternoon April 13th 2017.

FY 2018 H1B Lottery Done without any announcement

USCIS have not announced H1B masters or regular quota counts, but looks like it started processing of the Cap subjected petitions. USCIS never did this way in the earlier years. They used to announce that the lottery is done and first they will start with premium processing cases.

We can expect this kind of shocks or surprises from USCIS as it lawless organization and will violate it's own rules.

You can find out from your employer whether the check sent with your H1B application is cashed or not. If Check is cashed means your petition is selected in the lottery and being processed.

Good luck with your application.