[SOLVED] Project indicates changes made immediately after being opened

Got a really strange problem with a project in Sonar Platinum and wondered if any other forum members could explain what's going on...
 
I start Sonar and load the saved project, which loads without incident, yet when loaded the filename indicates the project has been changed - i.e. the filename reads project.cwp* instead of just project.cwp. It's only this project that's acting this way, and even if I save the project as a bundle and unpack it elsewhere it does the same thing. I noticed that the project seems to load the Pro Channel settings last in the project, so I tried removing everything from the Pro Channel and saving the project, only to find when I reload it, it indicates changes have been made.
 
It's only a minor annoyance, but I've also had Sonar "lose" my interface after reporting a "r6025 - pure virtual function call" error with this project when CA-2A was present. I've since removed CA-2A from the project, and am trying a different compressor in it's place, and wondered if the r6025 error could be a factor in the project load issue.
 
I'm going to try rendering the softsynths to audio and save an audio only version of the project to see if a softsynth is causing the problem, but was hoping folks here could offer any pointers.
 
I've not really kept Sonar up to date (my membership expired in April) and at present I'm currently running 2016.03, so I'm not running the latest build at the moment...
 
Cheers,
Gary.

Often LFOs or other things going on in plug-ins can dirty a project.