You are right the enabling/disabling "Use Non-X views" does not affect queries execution.
What is the version of Teradata ADO.Net client and Teradata database?
Also you could try cleaning a temp folder at C:\Users\USER_NAME\AppData\Local\Temp. TDP uses the folder for caching query results. You could try to install a new version of TDP. You should not uninstall the old one. Different versions of TDP can be installed side by side.
Regards
Aleksey