Hi Prageet,
I looks like when you are passing the case from the main process to the sub-process of the Web process you don't unlock it in the queue to allow the web process to get a lock on it.
This can cause the above error as if you are trying to populate queue data or compare queue data to data the object is gathering when spying it can't as the main process has the item ang the queue data locked.
A single unlock stage should help you out here.
Best Regards,
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Ronan Considine
Senior Business Analyst
Blue Prism
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Ronan Considine
Senior Business Analyst
Blue Prism