Sometimes when the Info Tip is loading, the text part (file info) of it loads faster than the thumbnail and momentarily appears close to the file item in the file display. This is momentarily before the Info Tip appears in full (file info + thumbnail) which loads in a different position on screen.
This looks a bit glitchy and only seems to happen when the Info Tip is already showing and the cursor moves to another item quickly, e.g. the next item in Details view. I imagine this is because of the time taken to move cursor from one item to another is shorter than the delay defined for the Info Tip's fade-in / fade-out timings.
That's intentional. If the thumbnail takes more than a short time to generate, the text will be displayed first, and then the thumbnail is added when it's ready. Otherwise you might have to wait several seconds to see anything, when you don't always care about the thumbnail and might need one of the text details.
This must be a somewhat recent change since I noticed it just after downloading the latest beta (I was on stable before). It certainly has some benefits because no longer do my multi-gigabyte video files cause Opus to hang (much): the text displays first -- nice. So whilst that's a big win, it does mean for smaller items that the Info Tip may display a little erratically due to how quickly both the text and thumbnail can load. Makes sense. It's a small detail, but such things grab my attention.
Just an idea: If the file size is known and it is relatively small, it could be used to delay the text from showing in such cases because it's reasonable that the image will load almost as quickly.