nsupdate hangs when processing a large number of updates interactively

Summary

On Ubuntu 22.04.4 since BIND 9.18.28, "nsupdate" hangs when processing a large
number of updates interactively.
All updates are performed.

This does not happen when updates are contained in a file.
This does not occur using nsupdate from BIND 9.18.27.

BIND version affected

root@haparanda:/home/named# /opt/bind/bind-9.18.28/bin/nsupdate -V nsupdate 9.18.28

Steps to reproduce

1. Use attached configuration file
2. Run the following command

{
  echo "server 127.0.0.1";
  echo "zone dummy.com";
  for n in {0..2000}; do
    echo "update add host$n.dummy.com 3600 IN TXT \"host $n\"";
  done;
  echo "send";
} |/opt/bind/bind-9.18.28/bin/nsupdate

What is the current bug behavior?

nsupdate hangs

What is the expected correct behavior?

nsupdate should return to the command prompt.

Relevant configuration files

options {
    directory "/home/named";
    pid-file "named.pid";
    recursion yes;
    allow-recursion { any; };
};


zone "dummy.com" in{
  type master;
  notify no;
  allow-transfer { any; };
  allow-update { any; };
  file "/home/named/m/db.dummy.com";
};

Relevant logs

using the "-DL 99" parameters the output is:

...
host1999.dummy.com.	3600	IN	TXT	"host 1999"
host2000.dummy.com.	3600	IN	TXT	"host 2000"
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: connected from 0.0.0.0#0 to 127.0.0.1#53: success
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: TCP response 0x7f366d1f1200: start reading
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: TCP reading without response from 0x7f366d1c1880
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: TCP response 0x7f366d1f1200: connect callback: success
02-Sep-2024 08:28:22.090 req_connected: request 0x7f366cd87000: success
02-Sep-2024 08:28:22.090 req_send: request 0x7f366cd87000
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: TCP response 0x7f366d1f1200: sending
02-Sep-2024 08:28:22.090 throttling TCP connection, the other side is not reading the data, switching to uv_write()
02-Sep-2024 08:28:22.090 dispatch 0x7f366d1f1000: TCP response 0x7f366d1f1200: sent: success
02-Sep-2024 08:28:22.090 req_senddone: request 0x7f366cd87000

RT 23930