Dependency problems in using aliases in static routes and alias visibility
As I opened Redmine Ticket https://redmine.pfsense.org/issues/9743 about that, you can read more details there.
Problem consists of missing dependency handling when editing, modifying or nesting aliases that are used in static routes (yes you can actually use host or network aliases there). While creating a host/network route works fine, if you edit an alias, your old route won't get deleted and a new one added. It will simply stay the way it was. After a reboot that gets fixed. It gets worse if you rename the alias in question and reboot -> then your route is gone without indicator as to why as there's no error visible. Also if you edit aliases and afterwars edit the route with the alias again, the new route(s) will get added but the old ones stay active and won't get removed. So it can get pretty messy ;)
Also wanted to mention, that it would be really nice if the GUI visibility of fields, that you can use aliases in (before switching to bootstrap as UI framework, those had a red background) would be awesome. It doesn't need to be a background color to the field in question as indicator. One could also use some icon etc. overlapping the text box to hint, that one can enter an alias in there. Especially people new to pfSense are often surprised to where you can use aliases as they would have never guessed (like static routes ).