This looks similar to issue addressed from Solution 288652. Solution mentionsseveral factors that might help you in this scenario. 

@Nishadi Sumanathilake do you have the information that solution 288652 provides so that I can review the factors as we are experiencing a similar issue.

Hi John,

In Solution 288652 it is mentioned that this kind of BRES Log errors could be caused due to many reasons, (please note that in the solution it is mentioned that issue occurred randomly for the user)

Factors that might cause this kind of behavior mentioned as,

- BRES was not running using a dedicated Administrator Account

- The dedicated user was not used to login to BRES and instead IFSAPP owner credentials were used.

-Excel Service not been able to process the request at that time due to an issue with Excel

Following document provide more detail in to BRES Windows Service User,

https://docs.ifs.com/techdocs/foundation1/020_installation/400_installation_options/007_br_and_a/010_IFS_Business_Reporter/030_br_execution_server/010_BRES_installation.htm

Hope this would be helpful to you.

Best Regards,

Nishadi

This may be helpful for others running into the same issue:

We need to restart Server hosting BRES every time the issue occurs and this usually fixes it up.

The crux of the issue is this post on MSDN:

Microsoft does not currently recommend, and does not support, Automation of Microsoft Office applications from any unattended, non-interactive client application or component (including ASP, ASP.NET, DCOM, and NT Services), because Office may exhibit unstable behavior and/or deadlock when Office is run in this environment.

If you are building a solution that runs in a server-side context, you should try to use components that have been made safe for unattended execution. Or, you should try to find alternatives that allow at least part of the code to run client-side. If you use an Office application from a server-side solution, the application will lack many of the necessary capabilities to run successfully. Additionally, you will be taking risks with the stability of your overall solution. Read more about that in the Considerations for server-side Automation of Office article.

I will leave this Question unanswered as there is no permanent fix to this annoying issue.