--- modules/http/http_filters.c	(revision 512953)
+++ modules/http/http_filters.c	(working copy)
@@ -185,7 +185,8 @@ 
          * Only valid on chunked and C-L bodies where the C-L is > 0. */
         if ((ctx->state == BODY_CHUNK ||
             (ctx->state == BODY_LENGTH && ctx->remaining > 0)) &&
-            f->r->expecting_100 && f->r->proto_num >= HTTP_VERSION(1,1)) {
+            f->r->expecting_100 && f->r->proto_num >= HTTP_VERSION(1,1) &&
+            !(f->r->eos_sent || f->r->bytes_sent)) {
             char *tmp;
             apr_bucket_brigade *bb;