My understanding is your wallet is calculating staking anytime it deems it appropriate.  Once it realizes it is not in sync it will adjust itself to account for the fact that the "current" staking is not valid.

This is not strange at all.

What you are seeing is not 'current' staking, but what 'had been' staking, and the reward/transactions that had occurred as your wallet updates to the latest block in sync.

Any wallet cannot perform such actions as staking and mining with it reaching the rest of the networks blocks due to consensus.

#crysx