Using wallet 3.9.0 and its synced accordingly to the explorer. No problems so far. With the previous wallet version 3.8.7.6 i was able to stake and get rewards but now i upgraded to 3.9.0 and it does not stake. The small lock says the wallet is unlocked for staking but the staking icon (gray with an arrow facing up) says staking and multisend not active and it does not turn green like the previous version of the wallet.
I really did not understand why your wallet does not have a stake activated as you change the status from lock to unlock Do you use the unlock option only for stake?and another thing you didn't tell me the amount of surplus you have because depending on the amount it takes to receive some reward!