I Created a Custom Field, image below:

I created an Automation to fill this new field with the Fix Version release date. I'm using this value to fill the date: {{issue.fixVersions.releaseDate}}. The automation is returning the following error: "(The Version End Date must be of the format "yyyy-MM-dd" (customfield_10035))"
I tried to select the Date Format for the Custom Field (Version End Date) but I could find how to set. Somebody knows how can I fix this error?