Cause: EBS volume attachment data cannot be cached reliably. Additionally after a claim is released it retains a referenc to the claim to which it was bound.
Consequence: Volumes that had been detached were not made available as they should have been. Also, if a claim is deleted and the volume it was bound to is released and another claim is created with the same name it will try to bind the old PV.
Fix: We no longer rely on cached volume attachment data and instead check on each request to mount or unmount an EBS volume. We also now check the claim's UID when trying to bind a PV based on the claim to ensure that the correct claim matches the correct PV
Result: EBS volume attachment tasks are much more reliable.