Duplicate Outputs Appear

Hi,

I get a weird thing that happens from time to time.
I get a duplicate instrument output showing up in the output section of a different VST instrument.
I’m attaching a screen shot.
The only way of getting rid of it is deleting the output from the original instrument track.
(could it be because the instrument track the duplicate output appears on is an instrument track I have to disable before closing project (PLAY) and re-enable after re-opening the project, for if I don’t Cubase crashes when trying to re-open the project?)

Thank you,
Scott.

Windows 7, Cubase 8.5