I booked a SkyMiles award flight from PVG-ICN-TPE on KE and CI. Later I decided I wanted to stay in ICN longer, so I changed the booking to just PVG-ICN. However I'm not sure everything updated all the way. The few thousand miles by which it was cheaper were redeposited to my account immediately, but the eCredit for the taxes/fees difference has not showed up (although it's only $7-8 so I don't care about that amount too much).

Initially, in my account I saw the trip change from PVG-TPE to PVG-ICN, but it has now reverted to PVG-TPE. Prior to changing, I used the KE/CI PNR (which I had to contact DL for as they still don't show it anywhere) to add the trip to the KE and CI apps on my phone, and the ICN-TPE leg on CI still shows up on both of them as well. I'm even still able to change my seat on it via the CI app, but not via the DL app anymore. The updated seat number is then reflected on KE and CI, but DL no longer displays it at all. If I try to change it via DL, it says the seat map is not available. These seat shenanigans with the CI flight are the only difference I've observed.

Would it be safer to just cancel it and rebook? I have enough miles to cover a temporary double booking, just not sure how much DL's cancellation fees are. (Edit: just researched and they seem to be quite hefty for tickets originating outside NA, so I probably want to avoid going that route)