The only other thing I thought of is to try balanced cables.
Maybe it does cross feed itself if unbalanced cables are used. I've never seen this, but maybe that's why they mention TR/TRS in their description of using the Line Level inputs. Like I said, adding the TR/TRS part to the Line Level description made no sense to me at the time, but maybe that's why they mention it(?)

No chance tonight, but maybe soon I can test for you. I've been so busy I've yet to even plug anything into my 2i2 (since I got it for Christmas). I installed drivers and grabbed plugins, but that's about it.

I do not work here, but the benefits are still awesome
Make your sound your own!