Hmm... Ok. Couple of suggestions, next time it is on the day of the job:
1) have a shower just after 9am, might trigger the change in clothes.
2) at 10am (or when the job starts) go into map view and just double check whether the marker is there or not. If not:
3) go into the job tab, there is a briefcase button towards the bottom. It usually flashes slightly if there is available work to do (not 100% sure on this as I didn't need to use it). Might show what beach perhaps?
4) if the above do not work, try resetting the sim.
5) if reset doesn't help, try moving the sim out and then back into the house.
6) if none of the above works, maybe trying quitting the job and then re-registering for the job.
If none of the above helps.... I'm a little stumped! Let me know what happens