This is almost always due to multiple image requests going out on page load.
This could be due to a number of things - anywhere from link tracking calls to other components of your site sending hit data. The first thing I'd do is open your site with the Experience Cloud debugger and double check all the data that's going out. If you're seeing multiple hits on a single page load, that would be where your issue is coming from, since a bounce is considered only a single hit.