Most probably a combination of a Database administrator and a Pega Application Designer will be needed here to help you out.

Or if your system is severely suffering from performance issues - GCS can assist also.

I am not sure I understand your question correctly. While the starting activity can be an OOTB Pega activity, the details in the alert and the action item in AES would provide more context around its execution which will tell the core issue in the application. This should be ideally fixed by the developers of the application and if the root cause points to an actual core product issue or needs further clarity, a separate Pega product support discussion with ample details would help, so that the community can provide inputs as required.