There are so many anomalies , unfortunately diabetes isn’t an exact science , I’ve had similar experience and to be honest still haven’t found an answer , when my sugars go extremely high I tend to over compensate , I find when I know my sugars are dropping I can control them better and I don’t feel as **** as I do when they are high , my method isn’t recommended but it works for me , experience and experiment has found this out , it is one of the many unexplained situations diabetes throws up ,
Just keep checking sugars regularly and if still high after 4 hours I would probably take more insulin ,