For Ramblers, this was due to source media set to PAL (25 FPS) with Vegas configured to start new projects in NTSC at 30 FPS.
The Vegas configuration looked OK and caught me out when I remote accessed their computer. This was because the default shortcut on the desktop actually pointed to an empty template, rather then the Vegas application. When starting Vegas, rather than loading a new default empty template, it was opening an empty template that was set to PAL. I went round in circles for a bit exporting blurry photos from TandemVids and checking Vegas using the incorrect shortcut. If I'd simply ticked the option to start all projects with the settings from the empty template set to PAL, it would have fixed everything. Instead, we were incorrectly assuming Vegas was configured correctly.
Mick
Mick Hardy attached the following image(s):