@Mike O'Dea, Thanks for posting in Q&A. From your description, it seems you have changed the "Password Age Days" in LAPS policy. But it is not updated. If there's any misunderstanding, feel free to let us know.
Based on my checking, the Policies/PasswordAgeDays CSP support Replace action.
https://learn.microsoft.com/en-us/windows/client-management/mdm/LAPS-csp#policiespasswordagedays
It may take some time for the policy to be pushed to the devices as policies are not instantly applied and can take some time to propagate to devices. You can sync on the device and wait some more time to see if the new update policy will be updated.
If there's any update, feel free to let us know.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.