Possible reproduction steps:
(unfortunately I wasn't able to reproduce the issue constantly, according to my tests it is not deterministic what happens when the portal/module is shutting down):
1. Set up remote staging
2. Create a lot of content (1000 Web Contents should be fine), so the publication process won't finish instantly
3. Publish to Live
4. While the publication is still in progress, publish to Live again, this publication will get "Queued" status
5. Shut down the portal / stop the "Liferay Portal Background Task Service" module before the publication finishes
- telnet localhost 11311
- lb | grep "Liferay Portal Background Task Service"
- stop <ID>
6. Restart the portal / module
- start <ID>
The second publication is still in "Queued" status.
The publication starts automatically.