So I took a second listen to the piece, and I do hear lydian, but your use of it was so subtle it could be easily mistaken for one of the other modes. Like it's like you were trying to hide it in the harmony/bass and not really bring it forward, that's why I was having a hard time really convincing myself that you were using lydian upon the first listen. It may be a good idea to be less subtle about it so it's clear what mode you're in.