In the Address Bar go to edge://flags/#tab-hover-cards and change the dropdown for that option to "Disabled". Do the same for edge://flags/#tab-hover-card-images and once both are set to "Disabled", restart Edge (or close all Edge windows, then open a new one). The image should no-longer appear, and when you hover over a tab, all you'll see it the title of that page
If you're using one of the "test" versions of Edge, "beta" or "dev", then Microsoft may be doing "A/B Testing" where some users get this feature, and others don't. Hence why when set to "Default" some of your devices may have that behaviour, and others won't.
Yes, it's normal to have something different on the one PC compared to the other. Microsoft do something called "A/B Testing", where certain new features or changes only get made on something like 10 to 20% of installs of that version, hence the confusion...