From the looks of it, it seems to be a bug concerning the ‘%’ (or more appropriately, the encoding for the % in URL which is %25).
I’m just basing this off the fact that, even though you are intending to search strictly for ‘100%’, it’s pulling up any games that start with ‘100’, ignoring the %.
Either way, agreed - definitely a bug.
Also, you may want to remove the client ID from the URL (unless it was created specifically to show this? )
The URL encoding is correct, since it gets the % character in the second query, so the bug is more likely on Twitch’s backend with how they use special characters in their search.
I do believe there’s also a bug with the “è” character as well, though I don’t have any good examples on hand.
(Client ids are public and should not be harmful to share)