Reproducible by demo apps.
Server: 03.WebSocket_High_Performance_Server\01.HTTP_SYS_WebSocket_Server
Client: 02.WebSocket_Protocols\01.SGC_Generic_PubSub_Protocol

In client enable watchdog (just the checkbox designtime).

Start server (admin).
Stop server and enable Authentication.
Start server.
Start client.
Connect to server port.

After some time (4 - 5 attempts) client runs on 100% CPU.

See video in link.
https://www.transfernow.net/dl/20241114c7RcQHy8