diff --git a/Cargo.lock b/Cargo.lock
index 92ec72449..bcc4f1d05 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -699,9 +699,9 @@ dependencies = [
 
 [[package]]
 name = "charabia"
-version = "0.8.2"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57aa1b4a8dda126c03ebf2f7e31d16cfc8781c2fe80dedd1a33459efc3e07578"
+checksum = "098219a776307414866165a03a9cc68c1578764fe3616fe979e1c280790ddd73"
 dependencies = [
  "aho-corasick",
  "cow-utils",
diff --git a/meilisearch/src/search.rs b/meilisearch/src/search.rs
index ab88cb671..c9ebed80e 100644
--- a/meilisearch/src/search.rs
+++ b/meilisearch/src/search.rs
@@ -680,6 +680,7 @@ fn compute_semantic_score(query: &[f32], vectors: Value) -> milli::Result<Option
         .map_err(InternalError::SerdeJson)?;
     Ok(vectors
         .into_iter()
+        .flatten()
         .map(|v| OrderedFloat(dot_product_similarity(query, &v)))
         .max()
         .map(OrderedFloat::into_inner))
diff --git a/milli/Cargo.toml b/milli/Cargo.toml
index fd6bee3eb..b19b40e85 100644
--- a/milli/Cargo.toml
+++ b/milli/Cargo.toml
@@ -17,7 +17,7 @@ bincode = "1.3.3"
 bstr = "1.4.0"
 bytemuck = { version = "1.13.1", features = ["extern_crate_alloc"] }
 byteorder = "1.4.3"
-charabia = { version = "0.8.2", default-features = false }
+charabia = { version = "0.8.3", default-features = false }
 concat-arrays = "0.1.2"
 crossbeam-channel = "0.5.8"
 deserr = { version = "0.6.0", features = ["actix-web"]}
diff --git a/milli/src/lib.rs b/milli/src/lib.rs
index cd97d6192..cfa438609 100644
--- a/milli/src/lib.rs
+++ b/milli/src/lib.rs
@@ -293,15 +293,15 @@ pub fn normalize_facet(original: &str) -> String {
 #[derive(serde::Serialize, serde::Deserialize, Debug)]
 #[serde(transparent)]
 pub struct VectorOrArrayOfVectors {
-    #[serde(with = "either::serde_untagged")]
-    inner: either::Either<Vec<f32>, Vec<Vec<f32>>>,
+    #[serde(with = "either::serde_untagged_optional")]
+    inner: Option<either::Either<Vec<f32>, Vec<Vec<f32>>>>,
 }
 
 impl VectorOrArrayOfVectors {
-    pub fn into_array_of_vectors(self) -> Vec<Vec<f32>> {
-        match self.inner {
-            either::Either::Left(vector) => vec![vector],
-            either::Either::Right(vectors) => vectors,
+    pub fn into_array_of_vectors(self) -> Option<Vec<Vec<f32>>> {
+        match self.inner? {
+            either::Either::Left(vector) => Some(vec![vector]),
+            either::Either::Right(vectors) => Some(vectors),
         }
     }
 }
diff --git a/milli/src/search/new/bucket_sort.rs b/milli/src/search/new/bucket_sort.rs
index 248dc4f7a..03e613b37 100644
--- a/milli/src/search/new/bucket_sort.rs
+++ b/milli/src/search/new/bucket_sort.rs
@@ -91,11 +91,12 @@ pub fn bucket_sort<'ctx, Q: RankingRuleQueryTrait>(
     /// Update the universes accordingly and inform the logger.
     macro_rules! back {
         () => {
-            assert!(
-                ranking_rule_universes[cur_ranking_rule_index].is_empty(),
-                "The ranking rule {} did not sort its bucket exhaustively",
-                ranking_rules[cur_ranking_rule_index].id()
-            );
+            // FIXME: temporarily disabled assert: see <https://github.com/meilisearch/meilisearch/pull/4013>
+            // assert!(
+            //     ranking_rule_universes[cur_ranking_rule_index].is_empty(),
+            //     "The ranking rule {} did not sort its bucket exhaustively",
+            //     ranking_rules[cur_ranking_rule_index].id()
+            // );
             logger.end_iteration_ranking_rule(
                 cur_ranking_rule_index,
                 ranking_rules[cur_ranking_rule_index].as_ref(),
diff --git a/milli/src/update/index_documents/extract/extract_vector_points.rs b/milli/src/update/index_documents/extract/extract_vector_points.rs
index 69fbff9b5..dd5a4d3a7 100644
--- a/milli/src/update/index_documents/extract/extract_vector_points.rs
+++ b/milli/src/update/index_documents/extract/extract_vector_points.rs
@@ -35,7 +35,7 @@ pub fn extract_vector_points<R: io::Read + io::Seek>(
         // lazily get it when needed
         let document_id = || -> Value {
             let document_id = obkv.get(primary_key_id).unwrap();
-            serde_json::from_slice(document_id).unwrap()
+            from_slice(document_id).unwrap()
         };
 
         // first we retrieve the _vectors field
@@ -52,12 +52,14 @@ pub fn extract_vector_points<R: io::Read + io::Seek>(
                 }
             };
 
-            for (i, vector) in vectors.into_iter().enumerate().take(u16::MAX as usize) {
-                let index = u16::try_from(i).unwrap();
-                let mut key = docid_bytes.to_vec();
-                key.extend_from_slice(&index.to_be_bytes());
-                let bytes = cast_slice(&vector);
-                writer.insert(key, bytes)?;
+            if let Some(vectors) = vectors {
+                for (i, vector) in vectors.into_iter().enumerate().take(u16::MAX as usize) {
+                    let index = u16::try_from(i).unwrap();
+                    let mut key = docid_bytes.to_vec();
+                    key.extend_from_slice(&index.to_be_bytes());
+                    let bytes = cast_slice(&vector);
+                    writer.insert(key, bytes)?;
+                }
             }
         }
         // else => the `_vectors` object was `null`, there is nothing to do