@Kates_Meltdown Hello! There is an open bug report for this issue. Please use the below link and click "me too" on the first post.
[OPEN] [PSP] Paranormal Investigator: Can't complete gig because missing pop-up - Answer HQ (ea.com)
@Gednaa mentioned in their post on page 2 of the thread that they were able to select the "leave late" option from the timer which then gave them the option to go home. Maybe see if that works for you and if it does give them some XP for their post.
I clicked the leave late option about 2 hours after the gig had ended and it worked the first time but not the second or third time.
