SIP sound is robotic until I put the call on hold

Dear sir/madam,

Hopefully this is the correct place to report a bug.

I am using Jitsi as my VOIP (SIP) phone.

I have a problem when I call someone over Jitsi, the person I called hears my voice just like a robot, (and no word is understandable). However, when I put the call on hold and then resume the call, he can hear my voice correctly again.

Is there any permanent fix or a better workaround for this?

Best regards