SFTP creates files with 0600 perms instead of 0644

I've just set up a new server for a client using a single domain Plesk license. Usually we use multi-domain licenses which of course include subscriptions and plans, so the settings I'm seeing in this install are a bit more restrictive but as far as I can tell everything is configured as per our usual.

We normally disable the FTP ports and just use SFTP for website access, but thus have the "Access to the server over SSH" settings set to "/bin/bash (chrooted)" or in some cases, just...

SFTP creates files with 0600 perms instead of 0644