The bug that I found would produce the opposite of CPU consumption; it causes the container shim to stop doing anything useful.
The docker info shows 17.11.0-ce, which is the buggy-af version, so you’ll want to downgrade, but not to fix this bug – this one’s a new one, and very definitely not Discourse-specific. If the problem persists, you’ll want to raise this on the Docker forums (it should feel familiar…), or if you can get a reliable reproduction of the problem, file a bug report.