There is a $500 per incident penalty for false patent marking. If a application is no longer pending then it would be a false marking to mark newly produced items with that mark. Of course you can file a non provisional at the end of the year or even another provisional application.
The law https://www.law.cornell.edu/uscode/text/35/292
I don’t know if there is a legal aspect, but for me you have a patent pending if you have an active application in process. From the USPTO site.
A provisional application for patent has a pendency lasting 12 months
from the date the provisional application is filed. The 12-month
pendency period cannot be extended. Therefore, an applicant who files