That’s unfortunate.I updated the E7 firmware just to realize the right channel of the 4.4 port is not working. At first I thought it could be the new firmware, but after downgrading to the previous version, the problem persisted. Unfortunately, it's a hardware problem and I really have no idea what happened. I would have to ask for a replacement or repair.
The 3.5 port is working normally. Yesterday I used the line-out for the first time by pairing the E7 with the Enleum HPA-23RM. Amazing combination and fantastic sound.
I assume you have tried different cables and IEMs just to exclude other failures?
Good luck with it!!!