Without URLEncoding you could end up with a link as follows
https://id.twitch.tv/oauth2/authorize?client_id=rf1123pvpvqytve34c1qn67bij9u&redirect_uri=http://localhost&response_type=token&scope=moderation:read
Which says
| item | value |
|---|---|
| client_id | rf1123pvpvqytve34c1qn67bij9u |
| redirect_uri | http://localhost&response_type=token&scope=moderation:read |
| response_type | none parsed |
| scope | none parsed |
Which would make an invalid link. and thus something else to check when having auth issues such as this