So not quite the same, but possibly related - I had a Sim building a rocket and progress seemed to freeze. I did have the option to continue building, unlike most people are reporting, but no matter how much time my Sim spent it never seemed to complete. But then she was flirting with her husband on the other side of the lot (rocket was off screen) and I noticed the "Woohoo in rocket ship" option... and clicked it, to see what would happen. The two walked over, and like magic, there was a complete rocket ship on the pad!
I do not have City Living. I do have Cottage Living. The save file I noticed this in was originally created before Cottage Living, and the family I'm playing has not been to Henford. I'm not sure if an egg festival happened or not as I wasn't paying attention to what the fairs were.
The LE I keep getting in this save is:
sims4.tuning.instances.autonomous_Bookshelf_Browse_Picker_Child'>
(TypeError: 'NoneType' object is not iterable)
Traceback (most recent call last):
File "T:\InGame\Gameplay\Scripts\Server\interactions\base\picker_interaction.py", line 2192, in _get_objects_internal_gen
TypeError: 'NoneType' object is not iterable"
...which makes no sense to me because my child doesn't read and half the time this fires at night when the whole family is sleeping. Also after extensive testing, I'm pretty sure this LE is only in this specific save and not related to my mods or CC.