I am a bit confused when you say you used change addresses. Did you transfer your coins to normal receiving addresses on your Trezor or to change addresses? It's the first time I hear about change addresses being displayed on a Trezor or Ledger software. You can see them in Electrum, but not in the native hardware wallet apps if I am not mistaken.

Maybe your firmware update messed something up. Again, I am unfamiliar with the workings of a Trezor and the "check seed phrase feature", but since you are certain you have the correct seed written down in multiple places, you could try to uninstall and reinstall the Trezor Suite and reset your hardware wallet to factory settings. After that, use the backup from seed feature, enter the correct seed, and see if that will bring everything back to normal.