1. The four backup cp calls (KEYFILE/CERTFILE/CAFILE/FULLCHAIN) ran
unguarded. With USE_SCP=yes MULTI_CALL is implicit, so each cp is its
own ssh call and a missing source aborted the deploy. In batched mode
it was masked because the exit code is that of the last command.
Each cp is now wrapped in a remote [ -f ] test.
2. deploy/ssh.sh tested DEPLOY_SSH_FULLCHAIN = "yes" instead of
DEPLOY_SSH_MULTI_CALL (since 2017). Effect was only that the
fullchain backup got deferred to the next batch. Fixed as well.
Please upgrade with acme.sh --upgrade -b dev and retest.