The issue is that QR's alphanumeric segments are uppercase only, and while browsers will automatically lowercase the protocol and domain name, you'll have to either have all your paths be uppercase or automatically lowercase paths. On top of that when someone scans the code it will likely be presented with an uppercase URL (if it doesn't automatically open in a browser) and that should alert anyone that doesn't already know that uppercase domains are equivalent to lowercase domains.
Ideally QR codes would have had a segment to encode URIs more efficiently (73-82 characters depending on how the implementation decided to handle the "unreserved marks"), but that ship has long sailed.
