Going to mark this as solved cause lately all reports have been mod related.
I came across a similar thing just now (for the first time). The sim suddenly stopped cooking (was using a frying pan) after changing from one ring to the next. I tried moving the cooker somewhere else in the house and it still route failed. Then I tried placing the cooker outside, with lots of space all around it, and after clicking the frying pan it worked and he immediately moved the frying pan to the counter.
This issue appears to happen (in this case) at the very end when the food needs to be served.
Edited to add, it now appears that once I got it working properly, he continues to cook food properly. Strange bug!
