diff --git a/pack-bitmap.c b/pack-bitmap.c
index fe8e8a51d3017f..1d6b7f2826850e 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -2073,6 +2073,7 @@ void reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
 		QSORT(packs, packs_nr, bitmapped_pack_cmp);
 	} else {
 		struct packed_git *pack;
+		uint32_t pack_int_id;
 
 		if (bitmap_is_midx(bitmap_git)) {
 			uint32_t preferred_pack_pos;
@@ -2083,12 +2084,24 @@ void reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
 			}
 
 			pack = bitmap_git->midx->packs[preferred_pack_pos];
+			pack_int_id = preferred_pack_pos;
 		} else {
 			pack = bitmap_git->pack;
+			/*
+			 * Any value for 'pack_int_id' will do here. When we
+			 * process the pack via try_partial_reuse(), we won't
+			 * use the `pack_int_id` field since we have a non-MIDX
+			 * bitmap.
+			 *
+			 * Use '-1' as a sentinel value to make it clear
+			 * that we do not expect to read this field.
+			 */
+			pack_int_id = -1;
 		}
 
 		ALLOC_GROW(packs, packs_nr + 1, packs_alloc);
 		packs[packs_nr].p = pack;
+		packs[packs_nr].pack_int_id = pack_int_id;
 		packs[packs_nr].bitmap_nr = pack->num_objects;
 		packs[packs_nr].bitmap_pos = 0;
 
diff --git a/t/t5332-multi-pack-reuse.sh b/t/t5332-multi-pack-reuse.sh
index 3c20738bcebd82..ed823f37bcdb96 100755
--- a/t/t5332-multi-pack-reuse.sh
+++ b/t/t5332-multi-pack-reuse.sh
@@ -204,4 +204,30 @@ test_expect_success 'omit delta from uninteresting base (cross pack)' '
 	test_pack_objects_reused_all $(($objects_nr - 1)) $packs_nr
 '
 
+test_expect_success 'non-omitted delta in MIDX preferred pack' '
+	test_config pack.allowPackReuse single &&
+
+	cat >p1.objects <<-EOF &&
+	$(git rev-parse $base)
+	^$(git rev-parse $delta^)
+	EOF
+	cat >p2.objects <<-EOF &&
+	$(git rev-parse F)
+	EOF
+
+	p1="$(git pack-objects --revs $packdir/pack <p1.objects)" &&
+	p2="$(git pack-objects --revs $packdir/pack <p2.objects)" &&
+
+	cat >in <<-EOF &&
+	pack-$p1.idx
+	pack-$p2.idx
+	EOF
+	git multi-pack-index write --bitmap --stdin-packs \
+		--preferred-pack=pack-$p1.pack <in &&
+
+	git show-index <$packdir/pack-$p1.idx >expect &&
+
+	test_pack_objects_reused_all $(wc -l <expect) 1
+'
+
 test_done