Not sure if that's what we want. We should probably update the docs to explain that the sequence_number is the one that will be used in a transaction.

Yes we should update the docs, but we also want bridge to work if no sequence number is passed to /builder endpoint. At the moment, this won't give a valid transaction xdr to submit to the network.

OK, then I think we should only increment sequence number if it was loaded from Horizon. Otherwise, it shouldn't be changed.