Hello @uzzie
Thank you for reaching out to the Community regarding your issue, although I am sorry to hear that you are experiencing issues updating the security.
I would recommend seeing if you might be able to update the security by going across the top of Quicken to tools > security list. Select the security and you should get the security overview. At the top you should get the option to update the security. Additionally there's also more tools to the right that should help with building the security under more that may help with getting the price corrected.
Once you're able to give these couple of suggestions a shot let us know if you're able to correct the pricing!
Thanks,
Quicken Francisco