Fix health check for rewards submissions

Author: 0xfornax

rocketpool/watchtower/submit-rewards-tree-stateless.go

@@ -173,6 +173,16 @@ func (t *submitRewardsTree_Stateless) Run(nodeTrusted bool, state *state.Network
 	currentIndex := state.NetworkDetails.RewardIndex
 	currentIndexBig := big.NewInt(0).SetUint64(currentIndex)
 
+	// Check if the node has already submitted the rewards for the previous interval
+	// In case we just had consensus, we want other nodes to also submit
+	hasSubmitted, err := t.hasSubmittedTree(nodeAccount.Address, currentIndexBig.Sub(currentIndexBig, big.NewInt(1)))
+	if err != nil {
+		return fmt.Errorf("error checking if Merkle tree submission has already been processed: %w", err)
+	}
+	if !hasSubmitted { // didn't participate in the previous consensus. Decrement the index and submit it as a health check
+		currentIndexBig = currentIndexBig.Sub(currentIndexBig, big.NewInt(1))
+	}
+
 	// Check if rewards generation is already running
 	t.lock.Lock()
 	if t.isRunning {
@@ -194,10 +204,6 @@ func (t *submitRewardsTree_Stateless) Run(nodeTrusted bool, state *state.Network
 		}
 
 		// Return if this node has already submitted the tree for the current interval and there's a file present
-		hasSubmitted, err := t.hasSubmittedTree(nodeAccount.Address, currentIndexBig)
-		if err != nil {
-			return fmt.Errorf("error checking if Merkle tree submission has already been processed: %w", err)
-		}
 		if hasSubmitted {
 			return nil
 		}