I regret not.
Ray has offered to help out by using Skype to see the problem but we have not had the time to go down that route yet.
We did load the Mac Pro up with 32Gb of ram (was 8Gb) which seems to have helped a little in our case, although it's difficult to tell, but the error seems to be a little less frequent. We have also adopted a policy of making a "Save All" before going back into the Server Behaviors panel. Again we are not sure if this helping the issue or not.
I am sure it is a Mac issue as I have not seen anything posted by Windows users. We did consider buying a Windows machine to use for development but that somewhat defeats the object! ;-) It would be interesting to hear from other Mac users who don't suffer the problem and see what OSX, testing server machine, server software, and Dreamweaver versions they are using - perhaps everyone develops on a Windows machine and it's only you and I on Mac's! (ha ha)
I will be in contact shortly regarding a Skype session with you. Sorry, but just a little busy at present. Thanks.