I just had a computer crash, and when I restored the computer I upgraded from I think Bitcoin 0.17 to Bitcoin 0.19.1. The wallet was gone, so I restored an old copy of the wallet. It's an HD wallet.
When the blockchain was synced, I put in the wallet in the proper folder, but the latest incoming transaction was not displayed. I generated several new addresses, but none of them had the latest transaction. I am sure it's the same wallet because it's got all the same transactions except the last one.
I then downloaded Bitcoin 0.17, and started generating new addresses starting with 3. The addresses were completely different, and had no overlap to the addresses generated with 0.19.1 from the same wallet.dat file.
I thought the point of a HD wallet was that I only needed to back it up once?
Any help is appreciated. The HD wallet issue might affect many users, many might think they are backed up because they use HD wallets. Best of all is that someone proves me wrong.