While not the most recent, I had SSSS on AKL-SFO in February, 2020 while flying home from a funeral. I hadn't been given SSSS since I was a child and shortly after 9/11, so it was quite surprising. Called UA and even checked with TSA, though nothing could be figured out. Luckily, AKL SSSS was just a ETD of my electronics and removal of my shoes (No NoS). When I landed at SFO, I had several hours before the flight to MCI and tried to have an agent remove my KTN and re-add it. This did not work. IIRC, I tried again with TSA and they mentioned there were two #'s listed on my profile. Somehow, my Dad's KTN got placed into the redress field on my PNR and it caused an issue. Not sure if it caused the SSSS, but once removed, PreCheck reappeared for SFO-MCI.