When I plug my external 3.5" hard drive into my 13" 2016 MacBook Pro, the Trackpad becomes very erratic and difficult to use. The drive is housed in a powered enclosure (brand Integral). Other external drives don't do this (2.5" without external power). Otherwise the MacBook functions normally, Bluetooth mouse works fine, the keyboard works fine.
I suspect this has something to do with the drive being powered externally. What could be causing this? And is it dangerous for the computer (or me)?
Edit: the drive won't mount when the MacBook is connected to external power. If I plug in the MacBook, the drive immediately ejects.