Intermittent 502 error in fellowship monitor

Bug Report

Description

Fellowship monitor is very slow and sometimes times out.

Steps to Reproduce

1. Navigate to https://scipost.org/edadmin/monitor/fellow_activity with sufficient permissions (senior fellow) and monitor network activitiy.
2. Observe that:

• The activity does not load
• The request to /edadmin/monitor/_hx_college_fellow_activity_table/physics takes a long time to complete, and sometimes results in 502 error.