I think You are right.
The best option, as suggested on previous posts, would be disabling E1.
You can do this poking with some variables (not recommended), or using the Axisconfigurator tool (recommended), that You will find at Setup > Service > Axisconfigurator. You need to be logged as Expert to use this.
We are all meeting today to clone the HD and deactivate the 7th Axis. Wish us luck.