diff --git a/milli/src/update/new/indexer/mod.rs b/milli/src/update/new/indexer/mod.rs
index 1122d3ac9..c2ca08c55 100644
--- a/milli/src/update/new/indexer/mod.rs
+++ b/milli/src/update/new/indexer/mod.rs
@@ -265,16 +265,18 @@ where
             let prefix_settings = index.prefix_settings(&rtxn)?;
             word_fst_builder.with_prefix_settings(prefix_settings);
 
-            let previous_words = index.word_docids.iter(&rtxn)?.remap_data_type::<DecodeIgnore>();
-            let current_words = index.word_docids.iter(wtxn)?.remap_data_type::<DecodeIgnore>();
+            let previous_words = index.word_docids.iter(&rtxn)?.remap_data_type::<Bytes>();
+            let current_words = index.word_docids.iter(wtxn)?.remap_data_type::<Bytes>();
             for eob in merge_join_by(previous_words, current_words, |lhs, rhs| match (lhs, rhs) {
                 (Ok((l, _)), Ok((r, _))) => l.cmp(r),
                 (Err(_), _) | (_, Err(_)) => Ordering::Equal,
             }) {
                 match eob {
                     EitherOrBoth::Both(lhs, rhs) => {
-                        if let Some(e) = lhs.err().or(rhs.err()) {
-                            return Err(e.into());
+                        let (word, lhs_bytes) = lhs?;
+                        let (_, rhs_bytes) = rhs?;
+                        if lhs_bytes != rhs_bytes {
+                            word_fst_builder.register_word(DelAdd::Addition, word.as_ref())?;
                         }
                     }
                     EitherOrBoth::Left(result) => {