I read that some consonants such as ㅈ are aspirated at the beginning of a sentence or phrase or something. However, I can't really find the explanation for this particular scenario where they sound aspirated.
For the first one ㅈ, I see a ㄱ before it, but I can't find the pronunciation rule for it.
I found this on Korean Phonology: When the second and third consonants are homorganic obstruents, they merge, becoming fortis or aspirate, and, depending on the word and a preceding |l|, might not elide: |lk-k| is [lk͈].
However, I don't really understand.