The teams endpoint still retrieves many duplicate teams and doesn’t display teams that exist. Two examples of teams not in the list are TwitchKittens and Khalico. Neither team exists in the /teams full listing, however they do both work if you call /teams/:teamname
Another random bug is case sensitivity. The team name needs to be lower case (/teams/twitchkittens works, but /teams/TwitchKittens returns 404).