Did you run ECS on a custom AMI, or use the stock one?
We've been running with vanilla EB + ECS for months and haven't seen this at all.
From an outside perspective, it sounds like the primary issue you referenced here (the agent disconnecting) could have been due to a mismatch in configuration between the agent and docker, or maybe just a permissions issue. IIRC, the ECS agent tries to clean up containers every few hours so perhaps not being configured correctly caused it to get stuck?
We've been running with vanilla EB + ECS for months and haven't seen this at all.
From an outside perspective, it sounds like the primary issue you referenced here (the agent disconnecting) could have been due to a mismatch in configuration between the agent and docker, or maybe just a permissions issue. IIRC, the ECS agent tries to clean up containers every few hours so perhaps not being configured correctly caused it to get stuck?