I received this email from their support team two days ago.
We're sending this message to you because you had posted in our Owners Forum about a missing review on your page. While we cannot say for sure that your property has been affected, we have identified a bug that resulted in some of our members' reviews being removed from the site. While this has affected only a small fraction of our community and properties on the site, we value every review and opinion and expect to have many of these posts republished as soon as possible. We apologize for the inconvenience to our community and the property owners, and appreciate your understanding. If you have any further questions I would encourage you to engage in further discussion in our Owners Forum - there is a stickied thread at the top of the forum about this topic..