I believe it is the same behavior that I have talked about earlier in the discussion about Uncertain_InitialValue. This no longer seems to be happening on the Primary gateway but my readItems method is never called when the Backup gateway is active. I am currently working on this issue with Travis Cox but I just want to be sure I am not wasting my effort trying to get this 7.9 code working in version 8.0 and version 8.1 verses just rewriting to the new OPC-UA device model.
I don’t think there is anything fundamentally broken with it. Our little generic TCP driver that is part of the UDP/TCP module is still written against AbstractTagDriver and AFAIK it works in both standalone and redundant setups.