diff --git a/src/polypcore/memblockq.c b/src/polypcore/memblockq.c
index 517495ebb..90e1d9ebe 100644
--- a/src/polypcore/memblockq.c
+++ b/src/polypcore/memblockq.c
@@ -548,6 +548,8 @@ void pa_memblockq_flush(pa_memblockq *bq) {
 
     assert(bq->n_blocks == 0);
 
+    bq->write_index = bq->read_index;
+
     pa_memblockq_prebuf_force(bq);
 }