Any help on this request.
If you are unable to reproduce or understand the problem, then how on earth do you expect us to be able to help with no access to the application or knowledge of what it does and how it works?
Run the Advisor on the app to identify any obvious problems.
Add further debug logging to the relevant areas of the app, enable the maximum debug level, and run in debug mode whilst you are trying to reproduce the problem. This will enable you to identify exactly where the problem is when it does occur.
Run the following in workspace to pin-point the cause
select page_id,ERROR_ON_COMPONENT_TYPE, ERROR_MESSAGE, APPLICATION_ID, ELAPSED_TIME from apex_workspace_activity_log where ERROR_MESSAGE is not null order by elapsed_time asc;