Thats awesome you provided a video, much appreciated and super helpful. I see what your seeing now, if perform the same actions in the Chrome, Safari or Microsoft Edge/IE11 browsers, you'll see the layout/rendering you expect. The issue you see is an rendering difference with the firefox browser and they way firefox is interpreting the inline style you've applied to the html, not an issue in the Auctiva item description editor. Your good to go, buyers using Chrome, Safari or Edge (about 90% of the ebay traffic) will see the description as you intended.
You might be able to change some of your inline styling to get a consistent look across all browser (at least the big 4 of Chrome, Safari, IE/Edge, firefox), for example the height attribute is not supported in HTML5 and modern browsers (see
https://www.w3schools.com/tags/att_td_height.asp), you might be able to get a consistent layout using inline CSS like
style="display: block;max-height: 5px;"
on your <td> tags.