curl: SSH host-key policy is missing from the connection-reuse tuple: strict pins and knownhosts are silently skipped on reused SFTP/SCP connections

The core effect is a silent host-authentication bypass: a transfer whose configured SSH host-key policy would reject the server is served anyway, with exit code 0 and no warning, because it reuses a pooled connection established under a weaker or absent policy. curl may assess this lower because ...