Teacher’s Pet Discovery quest issue

When I go to the downtown high school to check on my 5 sims that are currently on “perform sports action” task at over 17 hours long,  two of them suddenly cancels their task after being a few hours in. I restarted the two sims on the task needed and left. A few hours later, after coming back to them to check on their timer and two more sims suddenly cancels their task. I did not click on the red x or anything but now I had to restart these two sims on the task again! There’s less than 2 days remaining on the deadline and I’m afraid to go check on them later again in case it does it again. All 5 sims initially started at the same time but now, 3 of them are behind. What am I supposed to do about this?