I'm glad that your system is now working. To figure out, what is causing the connections with the login\database user, I'd suggest you to check if you can see some correlation between the statements executed from the user and your code base. Are there some code parts where you are not working with impersonation? Maybe executing code before using an impersonated connection?
Usually Telerik OpenAccess ORM does not generate any 'hidden' connections. Since we don't know how the underlying driver behaves with impersonation, it is hard to give you an advice here. Possible causes could be that connections are opened in a background thread and the thread was obtained through the IIS. The impersonation information could be lost.
I hope this information is helpful for you.
the Telerik team
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