RPA Blue Prism with Appian UI

Appian as a product suggest not to use any tool for screen grabing. And If I have understood correctly, you are doing same.

Clients commonly use Blue Prism to get data from Appian with Web API's (exposed as Restful services) instead of reading screens, as this is a much more scalable approach. I recommend you review Appians documentation on how to do this:
docs.appian.com/.../Web_APIs.html