Say I create a project, save it, do some stuff like record a guitar region, add a Drummer track, a synth bass part, put some third party plugs on the master bus, save the project again and finally save it as a template.
If my initial project was corrupted for any reasons but I didn’t encounter any problems while I was building it, then I have a corrupted template, without knowing it. So, all projects created using this template will be potentially corrupted.