Hi, I booked my wife on an itinerary with Delta on domestic segment, and Korean Air on the international segments.The itinerary is SEA-LAX-ICN-SIN. DL on domestic first, KE on Prestige, the damage was 85K SkyMiles. Anyway, KE sent my wife a notification about the flight number change. ICN to SIN originally was on KE841, now it will change to KE845. If she logged in to KE, the itinerary showed KE845 already (naturally) but Delta - when she logged in using her SM account, still showing KE841.

Our questions:
1. Is it common for Delta to lag behind KE, meaning that updates on their website lag for a few days?
2. Do we have anything to worry about the reservation? We called SM, and the phone agent confirmed that there is a note about flight number change, whatever that means. She confirmed that there is no need to worry about anything, all things are confirmed and ok. Is it?
3. My wife called KE, out of curiosity why Delta was not updated. KE said that Delta needed to re-issue ticket, which SM agent said that there is no such thing needed.

What to do in this situation? The award space btw SEA to SIN looks completely akimbo by now. I saw itinerary in business class costing 300K SM and upwards (insert SM joke here).

Thank you for the help in advance.