question

so basically i’m wondering if the “following” list is always chronological or not. this guy i was talking to started following his ex awhile ago and she was at the top meaning it was a recent follow right ? well i said it made me uncomfortable and he was like ill unfollow her and her name disappeared i thought he unfollowed her. well recently i was looking through her followers list and he was at the top i was like hmm that’s weird i didn’t notice when he started following her so i looked in his following and she wasn’t at the top, i had to scroll down kinda a lot to see her name. im just confused does this mean he never unfollowed her or is the list not always in chronological?? is it a glitch or something??