The reason for him appearing in 2017 doesn't make sense. But one thing for sure, it's a good comedy drama for anyone who prefer light-hearted drama. sounds confusing but if you think about it, hyun jae with wooseung right now is hyun jae from 1993, which would mean at the time he was single (not with bo hee therefore not ji hoon's dad) if it was the hyun jae from 94 who loved boo hee and fathered jihoon coming back and romancing wooseung then yea i would say its weird and gross but if you think about it, its not so i think their love is completely fine.
Hopefully turning off the "Use Mobile Data" switch as per the instructions below would force this unavoidable download to Wi Fi only, however it's difficult to confirm this because there's no clear information on the Apple Support website.