Unfortunately after 6 months your boinc contribution is erased if you not stake.
The staking is pure PoS now, but the amount you get when you stake is calculated from magnigude and time. The network remembers your contribution up to 6 months back and when you stake you will be paid for all of that.
As I said, i agree with you that the system is not perfect and we are working on improving it. Until the change is made, you can use polls to avoid the issues or buy enough coins to stake.
Just to clarify, instead of 1 grc every day, you will get 60 grc every month for example.
thanks for the explanation