You have added a space in front of the host key. You can see in the old log that the space was not there before.
open sftp://... -hostkey=" ssh-rsa 2048 ..."
Thank You!! Turns out all the keys are stored in the DB with a space in front of the "ssh-rsa"
I thought that only the part after the 2048 counts for the key. I'll fix them all. Thank You Martin!