To clarify:
I just investigated this further and it seems to be something to do with the latest version of t-rex custom miner the devs have added to the custom miner repository. There seem to be a bug in the h-stats script not sending correct number of array elements back to the HiveOS API causing this to happen. My mistake was that this coincided with the upgrade and i blamed it on Hive2. So its not a Hive2 issue, its a custom script bug.