AFAIK, Trezor implements it differently than Electrum's method.
It signs the legacy format of the address using the same private key of the SegWit address.

I'm not sure if it's Trezor or another Hardware wallet though.

For the meantime, here's an open-source "verifyer" of messages signed to SegWit addresses using Trezor wallet (not mine).
https://jhoenicke.github.io/brainwallet.github.io/#verify <- Different than the regular brainwallet/#verify link.
I already tried it, and it worked.