External keyboard

I purchased an external keyboard for my new iPad 9th gen running iOS 15. It has a problem in that certain keys don’t work, namely 7,8,9,u,i,o,j,k,l,m,. and Space. If I connect it to an iPad 5th gen running iOS 14.8, I don’t have the same problem. This leads me to thing that there is a compatibility issue with iOS 15. Any ideas?