Yes, right-clicking then choosing 'open in new window' did give me the non-ajax form from which I could add them.
I didn't try subscribing them from email but that might also have worked. Or it might not, depending on how the email syntax handles spaces.
Perhaps if spaces are not intended to be supported but people have created them those teams should be migrated?
I suspect what may have happened is this: the web ui forbids spaces in names. However it also forbids names containing the word "canonical". If someone asked a LOSA to create that team by hand, they may have bypassed the checks.