1.4.11 Non-text Contrast says that "states" of interactive elements must have a 3:1 contrast with adjacent colors. In the definition of states it says "hover" is an example.
While the "understanding" section of 1.4.11 (which is non-normative but still helpful) does say that mouse hover indicators do not need to contrast with the default state, it qualifies that by saying when the colors "do not appear next to each other". That is, if you have a button with one color and a hover state with another color, the hovered and non-hovered colors don't have to contrast with each other because you never see them at the same time.
But in your example, you do see both states at the same time because you can see hovered and non-hovered elements at the same time.
Is the hover color only available by mouse hovering? Can I see the hover color by tabbing to the dropdown then arrowing down through the list (keyboard focus)? If you can see the hover color using the keyboard (which I guess is not really "hover"), then you must have sufficient contrast between the hovered and non-hovered states.
If you can only see the hover color when using a mouse, then this might not be as severe a problem because the hover color also has a mouse ptr. That is, the hover color isn't the only indicator that I'm over an element. My mouse ptr also shows where I'm hovering (although that's more of a 1.4.1 Use of Color issue). So if the hover color is only available when using the mouse, technically it doesn't fail 1.4.11 because the qualifier for 1.4.11 says "Visual information required to identify states". In this case the hover color is not required to identify the state because you also have the mouse ptr to identify the state. It's a bit nuanced but allows you to pass, but again, only if the hover color is seen when only using the mouse.
For keyboard users, they need an indicator as to which item they're on when you arrow down through the list. As mentioned above, if the hover color is used for keyboard navigation, then it does require sufficient contrast because the hover color is required to identify the state.
You could satisfy the requirement if the currently hovered or keyboard focused element used a bold font in addition to your light gray background color. The gray background isn't the only clue that the element has focus/hover. Something like this: