Due to current precaution measures set in place against the ongoing COVID19 pandemic, soldiers who are carrying out their mandatory military service duties are banned from taking vacations and accepting outside visitors. Instead, once a soldier's discharge date is near, he may take a vacation leave from his service prior to his official discharge. Afterward, he is not required to return to base, but he still remains an active duty soldier for the remainder of the vacation period.
Originally, SHINee's Onew was expected to be discharged from his mandatory service on July 20. But with the current COVID19 precaution measures in place, it seems that Onew will "unofficially" be back home early.
Onew marks the first member of SHINee to complete his mandatory military service duties, after enlisting as an active duty soldier in December of 2018. Fellow members Minho and Key are also currently carrying out their mandatory duties.
[UPDATE] A representative of SM Entertainment has confirmed on July 8, "It's true that Onew is on his final leave from mandatory service today. He will officially discharged from his solder status on July 20 without returning to the military base, per COVID19 protocol."