When creating a Workflow in HubSpot, you may select the type of workflow you wish to create. Two of those options are: Fixed-date and Property-based. Both of these workflow types will allow you to center the workflow around a date, as explained in this article.
Once you proceed to editing the workflow, look next to the section This workflow will center on the date (for a Fixed-date workflow type) or This workflow will center on the property (for a Property-based workflow type), you will see a check box labeled recur annually. If that box is checked to recur annually, the workflow will ignore the year set in the specified property/date and operate off the current year.
If the recur annually box is not checked, then the workflow will use the full date/property, including the year.
If it is a Property-based workflow and a contact has a property date value of Oct 22, 2014 with the recur annually box unchecked with a delay of 600 days, the contact enrolled in the workflow will have their action scheduled for execution on June 13, 2016. This is approximately two years after 2014, so the action will execute in 2016.
However, if the recur annually check box is checked, the workflow will execute the action 600 days after the current year of 2016, not the year found in the property value, which would happen on June 14, 2018, approximately two years after the current year (2016).