HTTP server stops responding when a single WebSocket connection is running on Portenta H7

I’m using a Portenta H7 with the Arduino Mbed framework and running the following simultaneously:

- HTTP server on port 80 over Wi-Fi
- WebSocket server on port 81 over Wi-Fi
- UDP communication over Ethernet

Observed behavior:

- Both servers start without errors.
- Each server works fine individually.
- When a single WebSocket client is connected, HTTP requests fail (WebSocket connections still work).

Request:
Is there a known limitation in the Arduino Mbed framework on Portenta H7 that prevents multiple TCP servers from accepting client connections simultaneously?