It’s no waste of time.
The fact that the behavior changed is interesting. Back when I used Rules DSL I think I recall this happening, but I use .items files. When I would update a file that defines an Item all of the .rules files that reference the Items defined in that file would reload too, triggering all the System started rules in the process. This makes some sense because important things like Member of triggers could require a reload of the .rules files when Group membership changes. I’ve no experience with REST API created Items though so don’t know what to expect with that.
I do agree though, unless a lot of people see the same behavior it probably not something critical but it’s probably worth filing an issue. I would guess it would go on the openhab-core repo. See How to file an Issue. It may be nothing, it may be a regression, it may be working as designed.