I got the game yesterday, and created a Da Vinci character - Testy McTestALot (it's the name I traditionally give my first character after installing a new EP).
The shop worked fine for the artist career. Then I switched to sculpture. The first day of sculpting I put everything she'd made into the family inventory, went down to the store and consigned them. One or two of the last paintings still at the store sold, but none of the sculptures sold.
After 3 or 4 days of nothing selling I decided to unconsign the items and sell them from the family inventory instead, to get her career levels moving. When I unconsigned, all the non-sculpture items she'd made (chair, sink, etc) went to the family inventory and could be sold, but the statues went to Testy's personal inventory and couldn't be sold, they couldn't be taken out of inventory, I couldn't do anything with them except consign them again. So I consigned them again, just to keep her inventory clear.
When I eventually finished with sculpting (including hitting level 10 of the career) and moved on to inventing, those statues still hadn't sold, and still showed as having 5 days left on consignment. Nothing from the inventing career sold either, but at least there was no family inventory/personal inventory issues to worry about with those.
It seems that it was switching to consigning items from the family inventory (i.e. the sculptures) that broke the consignment store for Testy.