I have one track solo'd in a project. I delete that track. I expect SONAR to rest the SOLO status of the project. The SOLO button is still green even though no tracks are solo'd after deletion of that track.
 
Am I wrong to expect SONAR to reset that status?

I can't reproduce that. Was it audio, MIDI, Instrument or Simple Instrument track? No buses soloed? I think you must be missing something or that particular project has gotten into a weird state.

Good points about track types and such. I was thinking that any solo'd track deleted would cause a reset of the solo status. Thinking more about it after your comments got me to realize that the synth track was probably solo'd. It was out of view, so I did see that condition.
 
 I have a project with 10 tracks. The track was a midi track that got deleted. It was output to a synth and the synth was still solo'd after the track was deleted. I tried this with a midi track not output to anything and the solo status did change when the track was deleted. The synth solo track didn't haqve any tracks associated with it solo'd so I was wondering what others thought.
 
It is simple enough to click on the SOLO status button to reset the SOLO. I guess this would be an enhancement request on my part.

A soft synth being soloed after its tracks were deleted was one of the possibilities that occurred to me, but I checked this and it wasn't a problem.
 
Yes, the "orphaned" synth remained soloed, but the global solo indicator went out when the tracks were deleted. Right offhand, I'm not really sure what it means for a synth to be soloed; I suspect it's just a shortcut to solo all the tracks associated with it from within the synth rack. In the absence, of those tracks, the synth's solo state has no meaning and by itself will not cause the global solo button to stay lit.
 
I think there's still something else going on in your scenario.
 
 

The midi track I had was outside the synth folder. I solo'd that track which caused the synth folder to be solo'd. I will try to figure it our the exact  conditions that it happens and the results after I get these projects at a stopping point. Trying to get some songs ready for copyright and don't need a good mix just yet.

This is an older project I am revamping. It has been saved and reopened with X3 though.