I've noticed in both the backend catalog search and frontend search that incorrect product thumbnail images are being displayed for certain products if they do not have an image associated with them. Instead, these products show the image thumbnail of the previously appearing product that does have an associated image.
For example, in the below image all of the thumbnails are correct bar the one outlined in red, this particular product should show the Magento 2 placeholder instead as there is no image. But because there is no image it repeats the thumbnail for the last product rather than the placeholder.
I'm scratching my head figuring it out so any pointers on where to start looking to diagnose the issue would be greatly appreciated.