I think this is bug?

Had you moved the household to a new home? If you had, did this occur after they moved?

yes i add cat in my household

How much did you have before ?

Did you adopt the cat or how did you add it ?

Any mods/cc in your game ?

i have some mods and no adopt it and i have max simoleons 999.... always

So you basically have more than max money showing ? Is that what you are reporting ? Really not sure what you mean so maybe you could explain in more details ?

Could you please test without mods/cc ?