I was reviewing the code changes between 7.76 and 7.77 and decided to use different debug compiler settings to see if this could trigger an issue. Lo and behold, this resulted in a very intermittent stack/heap gpf caused by a bug in the server list parsing routine. It's difficult to know whether this is related to the issue you are seeing, as there were so many changes in 7.77, but it is very possible. This has been fixed for the next beta.
