diff --git a/lib/ftp.c b/lib/ftp.c
index 2c6138e980..3dd7fed045 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -4117,7 +4117,7 @@ static CURLcode ftp_disconnect(struct Curl_easy *data,
      will try to send the QUIT command, otherwise it will just return.
   */
   ftpc->shutdown = TRUE;
-  if(dead_connection)
+  if(dead_connection || Curl_pp_needs_flush(data, &ftpc->pp))
     ftpc->ctl_valid = FALSE;
 
   /* The FTP session may or may not have been allocated/setup at this point! */
diff --git a/lib/imap.c b/lib/imap.c
index fc38a5b61e..fa17b77151 100644
--- a/lib/imap.c
+++ b/lib/imap.c
@@ -1780,12 +1780,11 @@ static CURLcode imap_disconnect(struct Curl_easy *data,
   (void)data;
   if(imapc) {
     /* We cannot send quit unconditionally. If this connection is stale or
-       bad in any way, sending quit and waiting around here will make the
+       bad in any way (pingpong has pending data to send),
+       sending quit and waiting around here will make the
        disconnect wait in vain and cause more problems than we need to. */
-
-    /* The IMAP session may or may not have been allocated/setup at this
-       point! */
-    if(!dead_connection && conn->bits.protoconnstart) {
+    if(!dead_connection && conn->bits.protoconnstart &&
+       !Curl_pp_needs_flush(data, &imapc->pp)) {
       if(!imap_perform_logout(data, imapc))
         (void)imap_block_statemach(data, imapc, TRUE); /* ignore errors */
     }
diff --git a/lib/pop3.c b/lib/pop3.c
index aa8c2d834a..3e3070e333 100644
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -1450,7 +1450,8 @@ static CURLcode pop3_disconnect(struct Curl_easy *data,
      bad in any way, sending quit and waiting around here will make the
      disconnect wait in vain and cause more problems than we need to. */
 
-  if(!dead_connection && conn->bits.protoconnstart) {
+  if(!dead_connection && conn->bits.protoconnstart &&
+     !Curl_pp_needs_flush(data, &pop3c->pp)) {
     if(!pop3_perform_quit(data, conn))
       (void)pop3_block_statemach(data, conn, TRUE); /* ignore errors on QUIT */
   }
diff --git a/lib/smtp.c b/lib/smtp.c
index d39bb58d5d..99a348e234 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -1625,7 +1625,8 @@ static CURLcode smtp_disconnect(struct Curl_easy *data,
      bad in any way, sending quit and waiting around here will make the
      disconnect wait in vain and cause more problems than we need to. */
 
-  if(!dead_connection && conn->bits.protoconnstart) {
+  if(!dead_connection && conn->bits.protoconnstart &&
+     !Curl_pp_needs_flush(data, &smtpc->pp)) {
     if(!smtp_perform_quit(data, smtpc))
       (void)smtp_block_statemach(data, smtpc, TRUE); /* ignore on QUIT */
   }