oauth2orize redirect_uri issue - express

Question

I'm attempting to customize the oauth2orize all-grants example for my use. I can run the all-grants as-is and everything works (as you would expect), but when I run my customized version, I always end up with this error:
Error: Unable to issue redirect for OAuth 2.0 transaction
at Object.response [as handle] (C:\Dev\Expy\api\node_modules\oauth2orize\lib\grant\code.js:122:41)
I've been digging into this a bit and it seems there is a property of the txn variable within that function that should be named redirectURI and should be populated with the redirect_uri from the query string of the initial request to the /dialog/authorize page. For some reason this doesn't happen on my example app. Is this caused by an express version difference? That is the biggest difference that I see between the example code and my customizations. The all-grants uses express 2.* and my app will use express 4.*.
If it isn't an express version issue, where should I start looking in my code for the issue?
For reference, this is what I see in my app for the txn object:
txn: {
"transactionID": "evlUd2q4",
"client": { ... },
"req": {
"type": "code",
"clientID": "5C3B4438-433F-11E5-A532-74653C701F13"
},
"user": { ... },
"res": {
"allow": true
}
}
and this is what I see in that same object with the example (note the presence of the redirectURI in req and in the txn itself):
txn: {
"transactionID": "EEcYp3Uj",
"client": { ... },
"redirectURI": "http://localhost:3000/api/userinfo",
"req": {
"type": "code",
"clientID": "abc123",
"redirectURI": "http://localhost:3000/api/userinfo"
},
"user": { ... },
"res": {
"allow": true
}
}