Bad socket read/write on client local. A TLS error occurred.

I have the following setup:

• Broker 1: mosquitto configured as SSL server with ca, certificate and ca.
• Broker 2: mosquitto configured as bridge, with ca.

Both running as docker containers using latest image.

For some reason, after a while (not able to reproduce intentionally) I loose the connection and see in the logs of the Broker 2: Bad socket read/write on client local. A TLS error occurred.

Could someone help me to debug what is happening?

Thanks in advance