I don't think custom skins should be a problem, or the vo mod. But it might be related if it's causing enough changes to the game files to break the detection.
I would be able to tell if it's detected if you sent in your logs to us.
Things have evolved a bit since then, it will detect norms/ranked at random, sometimes it will lsometimes it wont. Could it be related to the custom skins and vo mod I installed?
Typically when it's only recording custom games and replays, but not ranked/regular games, that means it's not detecting League of Legends correctly. You could try using the Riot Repair Tool to hopefully fix it, or reinstall it.
However, if you want us to look deeper into this, you could also recreate the problem and then send in logs for us to investigate: How to Send Client Logs