Audio track sounds doubled but shouldn't be

This is the second time this has happened.  Can't figure it out so I'm hoping someone here can shed some light.
 
I've multitracked drums, and have created a composite take from about six take lanes.  Everything sounds fine, but after working on the track for a couple of weeks, the track for the last floor tom (there are four tom tracks) sounds doubled, or as if I was playing a flam each time it's struck. This particular track is panned almost hard right, and the tom is also audible from the other tom mics a bit, as well as the overheads. But what is weird is the "doubling" or "flam" effect, which appears to be positioned in the center.
 
The only way I can eliminate the doubling is by soloing the track.

I had exactly the same issue on my last mix of drums too which was 14tracks from drums only.
I thought i must have accidentally moved a track, no.
I ended up having to close sonar and reopen to fix.
I haven't tried any mixes since latest update and hadn't ever had problems before the last update either.
Not much help, i know!

"The only way I can eliminate the doubling is by soloing the track."
 
So what other tracks are picking up this tom?
 
If you mute this tom track and it's still audible in 2 or more other tracks, do you hear doubling on those?
 
If you don't then  it sounds like the track might have been nudged by a few ticks in the timeline - classic case of phasing issues, as already suggested.
 
 

You would not happen to have offset (mode) engaged on one or more of the tracks, making it play double?

You could check in the Inspector (I), or on the control bar. Do not know if it is your problem or not, but could be worth to check.

All the best.