Merge request queue expiring/auto-rejecting and should not.

Summary:

I had to purge the Contact Merge request queue. I started to put the requests back after fixing a data issue, but now it seems that the merge requests expire and auto-reject after a few hours. The process is manual and used to be able to accumulate in queue for a few weeks until the admin had time to process the requests. I need to set it back that way but do not know how or where to do that. The process is not set up on a scheduler so the expiration after a few hours should not be automatically