Examples, same PeerTube instance but different parent accounts (https://peertube.co.uk/)
Search for, find and able to subscribe:
https://peertube.co.uk/c/cinema
https://peertube.co.uk/c/linux_lounge
Search for, sometimes spinning forever, sometimes “No Results”:
https://peertube.co.uk/c/chrisweredigital@share.tube
https://peertube.co.uk/c/blender_channel@video.blender.org
Edit/update:
As I get more familiar with Lemmy and PeerTube, this turns out to be an artifact of federation.
The “@” obviously designates an account on a different server and when “https://peertube.co.uk/c/chrisweredigital@share.tube” won’t resolve, “https://share.tube/c/chrisweredigital” will.
Original title “Bug: Can’t subscribe to PeerTube channels with “@” in the name” changed.
You need to subscribe using the real actor location, not a federated one.