deploy hangs on copying paths

[onsails]

When I deploy configurations to some hosts with --remote-build, I see deploy hang on closure copy:

🚀 ℹ️ [deploy] [INFO] Building profile `system` for node `mylab` on remote host
[1/27/991 copied (2.4/9.7 MiB)] copying path '/nix/store/2izll9n7x1wv4dklyvznarwr7h9cyw68-source' to 'ssh-ng://user@host'

Deploys succeed without --remote-build. Manual nix copy of the same path and the very same ssh-ng://user@host succeed as well.

I've tried to adding -- -vvvvv --debug to the end of deploy command, no meaningful output provided.

I also tried:

            sshOpts = [
              "-oControlMaster=no"
              "-oControlPath=/nowhere"
            ];

which didn't help.