Combobox selection list conflicts with autocomplete list

If you have a combobox that has AutoCompleteMode set to SuggestAppend and you click the down arrow to drop down the regular list and then type a semi-match, the autocomplete list opens on top of the regular list. If you then use your mouse to select an item in the autocomplete list it actually selects an item in the regular list. See the attached screenshot, note the blue selection is in the regular list that is under the autocomplete list. Some of my users are complaining that they type a semi match and then choose the match with their mouse and they get the wrong selection.
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