Merge pull request #2703 from mkalinin/attest-after-execution

State that validator must consider only fully validated blocks

specs/merge/validator.md

@@ -122,6 +122,8 @@ def get_payload(self: ExecutionEngine, payload_id: PayloadId) -> ExecutionPayloa
 
 All validator responsibilities remain unchanged other than those noted below. Namely, the transition block handling and the addition of `ExecutionPayload`.
 
+*Note*: A validator must not propose on or attest to a block that isn't deemed valid, i.e. hasn't yet passed the beacon chain state transition and execution validations. In future upgrades, an "execution Proof-of-Custody" will be integrated to prevent outsourcing of execution payload validations.
+
 ### Block proposal
 
 #### Constructing the `BeaconBlockBody`