I have not been able to reproduce the problem. do you have scaled versions of the thumbnail image for different screen densities? If so, what sizes do you have and what are the dimensions of the button.
The closest I was able to come to reproducing the problem was if I had an image that was much too large in some densities, and much too low in others. For example, if you take the image you provided and assume it is XXHDPI (as I had asked for) then the image is a bit small, and is smaller than 13dp on XXHDPI (on XXHDPI, 13dp is 39 pixels, the image is 29 pixels). This sort of looked like the image you have for the 10 inch display, but not quite as extreme.
I wasn't able to reproduce the display issue you have on the 7 inch display.
I assume, now, that the problem isn't with the part of the layout you sent, but rather the rest of the layout stealing or giving room, and the seekbar fills or contracts with the excess space. For example, if I put layouts above and below the group you posted and then made the layouts larger and smaller, then I could mirror the problem you have exactly.
You should use a defined size (in dp) for this component [edit: rather than using layout_weight] so the component's 9patch doesn't expand or contract with space [edit: but maintains a consistent physical size]. This may mean you need to adjust the rest of the layout to fit.