diff --git a/src/core/ddsc/src/dds_read.c b/src/core/ddsc/src/dds_read.c
index 09139f5..ae386ca 100644
--- a/src/core/ddsc/src/dds_read.c
+++ b/src/core/ddsc/src/dds_read.c
@@ -84,7 +84,10 @@ static dds_return_t dds_read_impl (bool take, dds_entity_t reader_or_condition,
       if (rd->m_loan)
       {
         if (rd->m_loan_size >= maxs)
-          buf[0] = rd->m_loan;
+        {
+          /* This ensures buf is properly initialized */
+          ddsi_sertopic_realloc_samples (buf, rd->m_topic->m_stopic, rd->m_loan, rd->m_loan_size, rd->m_loan_size);
+        }
         else
         {
           ddsi_sertopic_realloc_samples (buf, rd->m_topic->m_stopic, rd->m_loan, rd->m_loan_size, maxs);
diff --git a/src/core/ddsc/src/dds_sertopic_builtintopic.c b/src/core/ddsc/src/dds_sertopic_builtintopic.c
index 325d536..25c29e6 100644
--- a/src/core/ddsc/src/dds_sertopic_builtintopic.c
+++ b/src/core/ddsc/src/dds_sertopic_builtintopic.c
@@ -93,7 +93,7 @@ static void sertopic_builtin_realloc_samples (void **ptrs, const struct ddsi_ser
 {
   const struct ddsi_sertopic_builtintopic *tp = (const struct ddsi_sertopic_builtintopic *)sertopic_common;
   const size_t size = get_size (tp->type);
-  char *new = dds_realloc (old, size * count);
+  char *new = (oldcount == count) ? old : dds_realloc (old, size * count);
   if (new && count > oldcount)
     memset (new + size * oldcount, 0, size * (count - oldcount));
   for (size_t i = 0; i < count; i++)
diff --git a/src/core/ddsi/src/ddsi_sertopic_default.c b/src/core/ddsi/src/ddsi_sertopic_default.c
index 81a40c7..3400a0d 100644
--- a/src/core/ddsi/src/ddsi_sertopic_default.c
+++ b/src/core/ddsi/src/ddsi_sertopic_default.c
@@ -42,7 +42,7 @@ static void sertopic_default_realloc_samples (void **ptrs, const struct ddsi_ser
 {
   const struct ddsi_sertopic_default *tp = (const struct ddsi_sertopic_default *)sertopic_common;
   const size_t size = tp->type->m_size;
-  char *new = dds_realloc (old, size * count);
+  char *new = (oldcount == count) ? old : dds_realloc (old, size * count);
   if (new && count > oldcount)
     memset (new + size * oldcount, 0, size * (count - oldcount));
   for (size_t i = 0; i < count; i++)