Debian Sid, linux-image-4.18.0-3-amd64 and LXC 3.0.2-1

With LXC 2, containers work as expected, but with LXC 3.0.2-1, when I try to start, for instance, mate-terminal, I get:

There was an error creating the child process for this terminal Failed to open PTY: No space left on device

What should I do to get it right?