do you think this would also be the case for RDH40's problem? did he ever say anything about pairing Ledger+Electrum?
his seed mnemonic might have been generated by electrum, which might also be a valid BIP39 Mnemonic phrase
so when he tried it on iancoleman's page it gives out the BIP39 version instead of Electrum version
Thats probably not the case.
OP mentioned the address has been generated by his ledger.
Regardless of whether you use the nano s with the chrome application or electrum, the device will still generate the seed/private keys itself.
Electrum is just a UI to access the nano s. Therefore the seed/keys generated by the nano s are always BIP39, regardless of which software is used to access the wallet.