Was ZFS determined to be the problem in the root cause analysis, or was it another part of the storage system that failed? It's easy to pass the blame down to t

Was ZFS determined to be the problem in the root cause analysis, or was it another part of the storage system that failed? It's easy to pass the blame down to the lowest level of the system because no one wants to take the blame. If it was actually determined to be the fault of ZFS, what was the problem? I'd like to avoid it in my own deployment.