It happens with NPCs at one of the beach lots in Sulani too. Mele Kahananui has cleaned this grill like 20 times now in a row with a scrub brush...*brushy brushy brushy*... pause.... thought bubble pops over her head showing she's thinking about her one true love, her precious, The Grill...then..... *brushy brushy brushy*
There is a temporary fix that should last as long as the maid or NPC sim is on that lot.
The way I was able to snap Mele Kahananui out of her scrub brush frenzy was to make the grill Dirty by shift+clicking on it and selecting "Make dirty". If you do this while they're actively cleaning it then it may not fix it that cleaning attempt, so try to do it before they start or reset the object interrupting them, then make it dirty. The cleaning attempt will take longer (like it normally does for a dirty item), and will clean the grill most of the time. Once that cleaning has finished they won't be obsessed with cleaning it anymore during that trip to that lot. Since this only lasts while they are on the lot if you have a maid make sure to have the grill dirty before their shift begins or early on in it so they don't get stuck on the grill for too long.
When testing this I noticed that this still works to break the loop when another NPC cleaned the grill instead, much to the horror of poor Mele Kahananui watching her beloved grill get scrubbed by someone else. Even though it wasn't Mele who cleaned it, that did break the loop too. So, as long as the grill gets cleaned while the obsessive Neat sim is on the lot then they will see the state of the grill as clean and not feel like they have to scrub it out of existence.
Its not a great work around but it at least should snap them out of it for that visit to the lot. Hopefully this gets fixed eventually. There are quite a few other obsessed sim type bugs too that can be very disruptive & sometimes destructive where the autonomy and desire to do something needs to be toned WAAAAY down like with insect farms on community lots. (Please stop "Nurturing" my beetles to death Mr. Bjorn "Lennie" Bjergsen..)
