diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -2105,7 +2105,7 @@
 			 *        SYN-SENT -> SYN-RECEIVED
 			 *        SYN-SENT* -> SYN-RECEIVED*
 			 */
-			tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
+			tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN | TF_SONOTCONN);
 			tcp_timer_activate(tp, TT_REXMT, 0);
 			tcp_state_change(tp, TCPS_SYN_RECEIVED);
 		}
@@ -2433,8 +2433,17 @@
 	case TCPS_SYN_RECEIVED:
 
 		TCPSTAT_INC(tcps_connects);
-		if (tp->t_flags & TF_INCQUEUE) {
-			tp->t_flags &= ~TF_INCQUEUE;
+		if (tp->t_flags & TF_SONOTCONN) {
+			/*
+			 * Usually SYN_RECEIVED had been created from a LISTEN,
+			 * and solisten_enqueue() has already marked the socket
+			 * layer as connected.  If it didn't, which can happen
+			 * only with an accept_filter(9), then the tp is marked
+			 * with TF_SONOTCONN.  The other reason for this mark
+			 * to to be set is a simultaneous open, a SYN_RECEIVED
+			 * that had been created from SYN_SENT.
+			 */
+			tp->t_flags &= ~TF_SONOTCONN;
 			soisconnected(so);
 		}
 		/* Do window scaling? */
diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c
--- a/sys/netinet/tcp_stacks/bbr.c
+++ b/sys/netinet/tcp_stacks/bbr.c
@@ -8902,7 +8902,7 @@
 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
 		 * there was no CC option, clear cached CC value.
 		 */
-		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
+		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN | TF_SONOTCONN);
 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
 	}
 	INP_WLOCK_ASSERT(tp->t_inpcb);
@@ -9088,7 +9088,10 @@
 					 tiwin, thflags, nxt_pkt));
 	}
 	KMOD_TCPSTAT_INC(tcps_connects);
-	soisconnected(so);
+	if (tp->t_flags & TF_SONOTCONN) {
+		tp->t_flags &= ~TF_SONOTCONN;
+		soisconnected(so);
+	}
 	/* Do window scaling? */
 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -11318,7 +11318,7 @@
 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
 		 * there was no CC option, clear cached CC value.
 		 */
-		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
+		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN | TF_SONOTCONN);
 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
 	}
 	INP_WLOCK_ASSERT(tp->t_inpcb);
@@ -11507,7 +11507,10 @@
 		    tiwin, thflags, nxt_pkt));
 	}
 	KMOD_TCPSTAT_INC(tcps_connects);
-	soisconnected(so);
+	if (tp->t_flags & TF_SONOTCONN) {
+		tp->t_flags &= ~TF_SONOTCONN;
+		soisconnected(so);
+	}
 	/* Do window scaling? */
 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1040,7 +1040,7 @@
 	TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, TCPS_LISTEN);
 
 	if (!solisten_enqueue(so, SS_ISCONNECTED))
-		tp->t_flags |= TF_INCQUEUE;
+		tp->t_flags |= TF_SONOTCONN;
 
 	return (so);
 
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -2978,8 +2978,8 @@
 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
 		comma = 1;
 	}
-	if (t_flags & TF_INCQUEUE) {
-		db_printf("%sTF_INCQUEUE", comma ? ", " : "");
+	if (t_flags & TF_SONOTCONN) {
+		db_printf("%sTF_SONOTCONN", comma ? ", " : "");
 		comma = 1;
 	}
 	if (t_flags & TF_LASTIDLE) {
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -515,7 +515,7 @@
 #define	TF_WAKESOR	0x00004000	/* wake up receive socket */
 #define	TF_GPUTINPROG	0x00008000	/* Goodput measurement in progress */
 #define	TF_MORETOCOME	0x00010000	/* More data to be appended to sock */
-#define	TF_INCQUEUE	0x00020000	/* on incomplete queue of listener */
+#define	TF_SONOTCONN	0x00020000	/* needs soisconnected() on ESTAB */
 #define	TF_LASTIDLE	0x00040000	/* connection was previously idle */
 #define	TF_RXWIN0SENT	0x00080000	/* sent a receiver win 0 in response */
 #define	TF_FASTRECOVERY	0x00100000	/* in NewReno Fast Recovery */