Some publishing builds are delayed when several builds are parallel in the publish step.
Checking the TCPDUMP of one agent shows the "TCP ZeroWindow" message.

I wonder how I can resolve this issue.

TCPDUMP

7150 251.659205055 AGENT_IP → MASTER_IP HTTP 7056 Continuation
 7151 251.659283229 AGENT_IP → MASTER_IP HTTP 7056 Continuation
 7152 251.659319307 AGENT_IP → MASTER_IP HTTP 1578 [TCP Window Full] Continuation
 7153 251.702816537 MASTER_IP → AGENT_IP TCP 66 [TCP ZeroWindow] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=0 Len=0 TSval=2031509725 TSecr=3318600647
 7154 251.949415340 AGENT_IP → MASTER_IP TCP 66 [TCP Keep-Alive] 30849 → 38970 [ACK] Seq=20564163 Ack=601 Win=64128 Len=0 TSval=3318600937 TSecr=2031509725
 7155 251.949522182 MASTER_IP → AGENT_IP TCP 66 [TCP ZeroWindow] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=0 Len=0 TSval=2031509971 TSecr=3318600647
 7156 252.461431856 AGENT_IP → MASTER_IP TCP 66 [TCP Keep-Alive] 30849 → 38970 [ACK] Seq=20564163 Ack=601 Win=64128 Len=0 TSval=3318601449 TSecr=2031509971
 7157 252.461537145 MASTER_IP → AGENT_IP TCP 66 [TCP ZeroWindow] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=0 Len=0 TSval=2031510483 TSecr=3318600647
 7158 253.453445838 AGENT_IP → MASTER_IP TCP 66 [TCP Keep-Alive] 30849 → 38970 [ACK] Seq=20564163 Ack=601 Win=64128 Len=0 TSval=3318602441 TSecr=2031510483
 7159 253.453558199 MASTER_IP → AGENT_IP TCP 66 [TCP ZeroWindow] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=0 Len=0 TSval=2031511475 TSecr=3318600647
 7160 255.437446516 AGENT_IP → MASTER_IP TCP 66 [TCP Keep-Alive] 30849 → 38970 [ACK] Seq=20564163 Ack=601 Win=64128 Len=0 TSval=3318604425 TSecr=2031511475
 7161 255.437554446 MASTER_IP → AGENT_IP TCP 66 [TCP ZeroWindow] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=0 Len=0 TSval=2031513460 TSecr=3318600647
 7162 256.457604326 MASTER_IP → AGENT_IP TCP 66 [TCP Window Update] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=272512 Len=0 TSval=2031514480 TSecr=3318600647
 7163 256.457747083 AGENT_IP → MASTER_IP HTTP 7056 Continuation
 7164 256.457767835 AGENT_IP → MASTER_IP HTTP 7056 Continuation
 7165 256.457778035 MASTER_IP → AGENT_IP TCP 66 [TCP Window Update] 38970 → 30849 [ACK] Seq=601 Ack=20564164 Win=552960 Len=0 TSval=2031514480 TSecr=3318600647
 7166 256.457857215 MASTER_IP → AGENT_IP TCP 66 38970 → 30849 [ACK] Seq=601 Ack=20578144 Win=734848 Len=0 TSval=2031514480 TSecr=3318605445