Hmm, do you mean that after you add a card, the content of first field stays as it is, and then you get the Show Duplicates button? If so this is perfectly normal, and Anki is rightly warning you that you have another card (the one you just added) with an identical first field. I guess the reason the content of first field is not getting cleared after adding a card is that you have the sticky field option activated. Click the Fields button in the editor, select the Front field, and make sure that the Remember last input when adding checkbox is toggled off.
Same thing here. Except there is no “Remember last input when adding” check box. Problem continues. I have to set all over again in each and evey card I add. It began today.