We are currently looking into an issue regarding applications deployments. They may be able to start but may never complete.
EDIT 15:05 UTC: The issue appears to be limited to the Paris zone
EDIT 15:20 UTC: A counter measure has been deployed to mitigate issues. Deployments are now scheduled as expected. Some errors may still appear in your Logs. We're processing stuck deployments, but you may cancel or start a new one if you want to prioritize your deployment.