The successful chat or conference services change your computer settings and only some services put them back when they're done.At lease the next time it happens
Their product, their job, and promotion/publicity depends on total control of the sound pathways to avoid distortion, noise, feedback etc. etc. They have almost no need to save where the computer was before they set up for chat. So they don't. You think you're doing something wrong because the chat worked perfectly and now that stupid Audacity won't record my YouTube Music. What's wrong with Audacity, anyway?
You have a leg up because you have two computers and you at least know that it's computer dependent.
Skype became the most popular conference system on earth working that way.
And yes, knowing how to put it all back together later is a definite advantage. Write it down.
Koz