Hello,

you can't rely on the link indexed by Google in the serp, that could be indexed even outside the sitemap.

You have to check the links for events included in the sitemap if they are correct or not, however the data source for Ohanah 3 is not the problem.

I think that the problem happens because you are using Ohanah with repeated events, so it's an issue exclusively related to Ohanah itself. Indeed when using repeated events Ohanah by default shows the last event date, in your case it could be the 5th May. that would be the event and date indexed by Google too.

Best regards
John