Electrum uses a different code to derive BIP39 seed.
Why? One would think you could look at the phrase used to create the wallet. Not exactly user friendly.
Well, to be fair, Electrum doesn't generate BIP39 seed.
If the seed phrase is created by Electrum, you can look it up no problem.
If the user used a BIP39 seed to create a wallet, that seed phrase isn't created by Electrum, so that wallet isn't an "
Electrum wallet"
but a "
Restored" (
not created) third-party wallet and the seed phrase should've been available to display in the original wallet.
If you want to change that feature, you can try to convince the main developers by following the replies in the link in my first reply.