I am noticing that when data values are changed in our Marketo org I am not seeing the changes sync back to Salesforce. I would expect that the 5 minute sync would take care of this action but I'm not seeing the results in the CRM. What should I check to make sure that those data updates are getting into SFDC?
The sync takes about 7 min to sync from the time that the last sync completed. When you include the time that it takes to for the sync to process you can experience slightly longer wait times before the data value updates appear in SFDC.
To check the progress of your Marketo sync with Salesforce you can go to the Admin tab of your instance and in the left nav panel click on "Salesforce" under "Integration".
There in the upper right corner, it will show you the last time your Marketo instance was synced with Salesforce and give you options to disable or re-enable the sync.
This way you can ensure that the sync is enabled between Marketo and Salesforce. The next thing to check is that Marketo has permissions to update the data values in Saleforce. For example, Marketo is unable to update customer fields at the campaign member level etc.