John Mueller tweeted yesterday. He stated if you have invalid markup then it would not cause manual action. John was asked a question in Twitter. Here is a screenshot of the same
There are general guidelines applied to structured data. These are crucial for inclusion in Google SERP. Google had informed that if you violate these guidelines you may receive less favorable rankings. You might also be considered ineligible for rich results in SERP. Manual actions may be applied if your page contains swampy structured data. You can check for manual action by opening Manual Action report in Search Console.
Also, even if marked correctly, there is no guarantee that your structured data will show up in SERP. This can be due to many reasons. For instance if your structured data is not representing the main content of your page if . Or, it is incorrect and the testing tool is unable to catch it.
