I can reproduct this bug in 11.22 with Delphi 7 on Windows 10 Pro. Tested also with a 5 month old Alphacontrols (bug also present), so it was not introduced recently.
You can see on the screenshots the distortion of the mainmenu icon after you go once with the mouse over the menu item (so the item gets the mouseover selection, and then loses it because you go with the mouse to the next menu item). Images are zoomed in by 400%. You see the ugly red line added to the bottom of the icon. It happens with all the icons. The problem is solved if SkinManager/SkinProvider is removed from the project (but the menu is not skinned then of course). I have attached screenshot and a test project with only Mainmenu, SkinManager, SkinProvider and TsAlphaImageList (for the icons) present.