diff --git a/consensus/types/src/beacon_state.rs b/consensus/types/src/beacon_state.rs
index f23b7878be..d4396f494f 100644
--- a/consensus/types/src/beacon_state.rs
+++ b/consensus/types/src/beacon_state.rs
@@ -266,6 +266,7 @@ where
     pub finalized_checkpoint: Checkpoint,
 
     // Inactivity
+    #[serde(with = "ssz_types::serde_utils::quoted_u64_var_list")]
     #[superstruct(only(Altair))]
     pub inactivity_scores: VariableList<u64, T::ValidatorRegistryLimit>,
 
diff --git a/consensus/types/src/participation_flags.rs b/consensus/types/src/participation_flags.rs
index 476e7757bb..74c2cf73ba 100644
--- a/consensus/types/src/participation_flags.rs
+++ b/consensus/types/src/participation_flags.rs
@@ -9,6 +9,7 @@ use tree_hash::{TreeHash, TreeHashType};
 #[serde(transparent)]
 #[cfg_attr(feature = "arbitrary-fuzz", derive(arbitrary::Arbitrary))]
 pub struct ParticipationFlags {
+    #[serde(with = "eth2_serde_utils::quoted_u8")]
     bits: u8,
 }