Ok... so it sounds like the address the coins have been sent to is NOT in your wallet... but IS generated by your seed... so that's a bonus!
The trick now, is to figure out which "Derivation Path" was used to generate that "incorrect" address from your seed... I did some testing with Mycelium and it seems that when using the iOS setting in conjuction with your xpub, the addresses generated are actually the ones that are generated from m/44'/0'/0' using your recovery phrase:
ie. Goto the BIP39 Mnemnoic Code Converter:
https://iancoleman.github.io/bip39/ (use offline version etc etc)
- Set the "BIP39 Mnemonic" as your 12 word Mycelium seed phrase.
- Click "BIP32" tab under "Derivation path"
- set "Client" dropdown to "Custom Derivation Path"
- set "BIP32 Derivation Path" to: m/44'/0'/0'
the "bad" address(es) (from using iOS setting in Gear widget), along with matching private key(s), should be listed at the bottom... NOTE: you NEED to use your seed (and NOT the xpub) so that you can see the private key(s)... once you have the private key(s), you can recover your misplaced coins by simply sweeping the contents of that "bad" address(es) back to the address of your choosing.
NOTE2: If you click the "BIP44" tab, you should see your "good" address(es) (from using the Android setting in Gear widget)