Hello, please check, if this is *really* expected behaviour.
If yes, feel free to close it or move to the propper component.
What I did:
* Running in Fedora 25 - Cinnamon
* dnf groupinstall gnome
* dnf groupremove gnome
* screensaver - gone
* terminal - gone (that was insidious!)
* some keyboard shortcuts - unreactive
* Cinnamon start locking with 2 different lockscreens (you unlock one and second appears)
Why does that happen: (no research done, just a thought)
* Cinnamon is based on the Gnome and much from the settings is same or simmilar.
* Also, many similar tools can obsolete their twins.
* If it is expected, i would at least add warning, that groupinstall may be dangerous, here:
The problem is in Anaconda, because it doesn't mark any group or env. group as a installed. The problem will be solved with fc26 for new system installation.
In your case you can fix it, if you will installed again your primary used env. group. In your case "dnf group install 'Cinnamon Desktop'". After that you can install other groups without fear, that your primary env. group or their component will be removed. Hope, that it will help.
Thanks for explanation.