Very similar articles posted within hours of each other

Hi....am still new here and finding my way around. My understanding was that with the 'recent drafts' section, it gave other people a heads up about what you were writing plus the 'duplicate article' check covered the same area. I was a bit surprised therefore this morning (European time) to find that someone had written an article very similar to mine and using the same picture and posted it two hours after I did. Is this something that happens often? Best wishes Amanda