Deployments do not start an elastic instance

In the OnDemand version of Bamboo, deployments do not seem to start elastic instances. They will use one if it is available, but will not start one if there isn't - even if there are no instances available.

This is making scheduled deployments useless for me - I've set up scheduled deployments to populate our test environments early in the morning, and they just stay queued until an elastic instance is available.