diff --git a/builder/builder.go b/builder/builder.go
index e765b4b..d83db27 100644
--- a/builder/builder.go
+++ b/builder/builder.go
@@ -614,7 +614,7 @@ func (b *Builder) OnPayloadAttribute(attrs *types.BuilderPayloadAttributes) erro
 			// Verify signature against the public key
 			valid, err := delegation.VerifySignature(pubkey, b.GetConstraintsDomain())
 			if err != nil || !valid {
-				log.Error("could not verify signature", "err", err)
+				log.Error("could not verify delegation signature", "err", err, "valid", valid)
 				continue
 			}
 
diff --git a/core/types/constraints.go b/core/types/constraints.go
index ea16c61..2a32dcf 100644
--- a/core/types/constraints.go
+++ b/core/types/constraints.go
@@ -21,10 +21,8 @@ import (
 	"github.com/flashbots/go-boost-utils/bls"
 )
 
-var (
-	// ConstraintsDomainType is the expected signing domain mask for constraints-API related messages
-	ConstraintsDomainType = phase0.DomainType([4]byte{109, 109, 111, 67})
-)
+// ConstraintsDomainType is the expected signing domain mask for constraints-API related messages
+var ConstraintsDomainType = phase0.DomainType([4]byte{109, 109, 111, 67})
 
 // NOTE: given that it uses `common.Hash`, `Transaction` and it's used in both
 // the builder package and the miner package, here it's a good place for now
@@ -252,7 +250,6 @@ func (c *SignedConstraints) Digest() []byte {
 
 	for _, tx := range c.Message.Transactions {
 		hasher.Write(tx.Hash().Bytes())
-
 	}
 
 	return hasher.Sum(nil)
@@ -279,6 +276,7 @@ type SignedDelegation struct {
 }
 
 type Delegation struct {
+	Action          uint8            `json:"action"`
 	ValidatorPubkey phase0.BLSPubKey `json:"validator_pubkey"`
 	DelegateePubkey phase0.BLSPubKey `json:"delegatee_pubkey"`
 }
@@ -287,6 +285,7 @@ type Delegation struct {
 func (d *SignedDelegation) Digest() []byte {
 	hasher := sha256.New()
 	// NOTE: ignoring errors here
+	hasher.Write([]byte{d.Message.Action})
 	hasher.Write(d.Message.ValidatorPubkey[:])
 	hasher.Write(d.Message.DelegateePubkey[:])
 	return hasher.Sum(nil)