Why are there so many TCP requests when connecting via socks5?

Question

proxy

Hello, there is server_1 and server_2.

server_2 connects to server_1 on a specific port via socks5.

And when server_1 sends some data to server_2, Hetzner sends us an email with this log:

log file

##########################################################################
#              Portscan detected from host     server_1               #
##########################################################################

time                protocol src_ip src_port          dest_ip dest_port
---------------------------------------------------------------------------
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 49074
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 47185
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48499
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48552
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48016
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48730
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48762
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48060
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48767
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 49039
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 47121
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48557
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 47740
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 49055
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 49338
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 49293
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48457
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48095
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48747
Sat Feb  5 01:02:28 2022 TCP     server_1 34922 =>    server_2 48473

1000 таких запросов

Why is the server_2 port always different?
What could be such a reason?
This is normal for the socks5 protocol, how can this be explained?