PI Tag that relies on the "SourceTag" attribute to pull data from another tag is only receiving "bad" values after an upgrade of an interface for our DCS interface.

For context, our current setup can be visualize as follows:

• TagA (holds original data), TagB (specifies "TagA" in the "SourceTag" field).
• Our interface pulls data from TagB

We have found that if we manually post a value for TagB - it is picked up by the interface just fine. However, when data is posted to TagA, TagB then receives a "bad" value.

Any thoughts on this? Any guidance would be highly appreciated.