There's a new exploit available which allows you to host missions that are higher than your level.
If you go into "Menu > ONLINE > Jobs > Host Job > Recently Played > Missions" you might see missions that you recently played that you can host, and those missions can be a higher level than the character you're playing.
I only have two in my missions list, Potshot (unlocks at 26) & Coveted (unlocks at 36) which I've been playing solo on my level 287 character, but when I switch to my level 23 character it's able to host those through the "Recently Played > Missions" menu, as all the recently played jobs are shared between the characters.
I've been solo playing other higher than level 23 missions, but for some reason they won't appear in the "Recently Played > Missions" menu.
Well anyway, enjoy it until they patch it