Kimberly Ann, unfortunately, the often said comment that Korean script is completely phonetic is false, if it is applied to spoken Korean. While it is true that the rules of phonetics in Korean script is precise, spoken conventions could vary, and sometimes in a predictable way as in the example. It is not an exception, and there will be similar examples with this pattern. This is why it is difficult for even native students to learn to spell correctly when "glottal stops" are in the word.
My advice is to just be aware of these mismatches and continue to advance in the language. Eventually, they will appear more natural and normal.