Be careful. There is something called the gap limit. Wallets will scan addresses derived from an xpub to try and locate all funds but if they scan N addresses and all are empty the wallet will assume the rest of the addresses are also empty. In this case it can look like your funds are missing. In reality that particular wallet just doesn't look far enough ahead.

We're looking into this issue now and will get back to you.

Great question btw! Much respect for going the extra mile to ensure your privacy. 🤜 🤛