this is just because of the shift of historical "ヱ" ("ye") getting pronounced as "エ" ("e") then just not used anymore. They're using "イ" as a semivowel here, /j

this is just because of the shift of historical "ヱ" ("ye") getting pronounced as "エ" ("e") then just not used anymore. They're using "イ" as a semivowel here, /j/, not as the vowel /i/.