This is something I just recently noticed, and I feel it’s a functionality of the built in auto save that should be changed or at least have the option exposed.
I recently have been working on a fairly large Blender file (2GB+) and when checking the temp folder to clear out some auto saves I noticed saves that were timestamped after the project had been saved and no new changes had been made. I watched the folder, and sure enough 5 minutes later another file was saved even though no changes had been made and the opened file was saved.
I haven’t paid much attention to how other software handles this outside of After Effects, and it doesn’t auto save unless the project has been changed since the last manual user save. The reason I see this as a problem is those that have their temp folder on an SSD for instance. If you leave Blender open in the background and your project has been manually saved it will just continually auto save at whatever interval you have set which means you are writing a lot of unnecessary data to your drive over time.
I am hoping to provide this feedback so potentially this behavior can be changed or a toggle option can be added to prevent this from happening.