Disable ECDSA SSH Host keys
Maybe not the best solution but substituting the key with empty files seems to work:

cd /etc/ssh/
sudo rm ssh_host_ecdsa_key
sudo touch ssh_host_ecdsa_key
sudo rm ssh_host_ecdsa_key.pub
sudo touch ssh_host_ecdsa_key.pub


The key is invalid and not used, but is not corrected/regenerate when starting up