קֽוּם־נָ֣א שְׁבָ֗ה וְאָכְלָה֙ מִצֵּידִ֔י בַּעֲב֖וּר תְּבָרֲכַ֥נִּי נַפְשֶֽׁךָ
יעקב tells קוּם נָא שְׁבָה וְאָכְלָה מִצֵּידִי ,יצחק. Mispronouncing it וְאֹכְלָה would drastically change the meaning from the second-person "you shall eat" to the first-person "I shall eat," as evidenced by its use in פסוק כ"ה. Fortunately, our בעל קריאה last year was - what my son would call - an oy-er, and a very consistent one at that, so the mistake stood out and I was able to catch it. But this is a mistake that an oh-er could very easily get away with, unfortunately.
It should also be noted (as Elie did below) that וְאֹכְלָה has a שוא נע under the כ whereas וְאָכְלָה has a שוא נח.
A reader has cleverly pointed out:
An amusing mnemonic device: The pasuk states: "קוּם־נָ֣א שְׁבָ֗ה" and not קוּם שְׁבָ֗ה נָ֣א -- It is not a שוא נע!