@EddieKal

Your question is a duplicate of this one: english.stackexchange.com/a/346535/365490

I can't improve upon Herisson's answer and he'll close your question shortly (Gold Pronunciation Badge owner)

@Wistful Awesome, thanks for the pointer!

It's alright if the question gets closed as a duplicate.

There are no fixed rules. Almost all the rules have exceptions. See for example 'super', it also have /j/ but the /s/ and /j/ didn't coalesce ... I don't know why.

@Wistful Yeah I think the interesting thing is we ask "why" questions and we get great answers that sometimes come down to a line "I don't know why". Like that answer by Herisson. "It's unclear why these words in particular show this change, and others don't in present-day English". But that by no means takes away from the greatness of those answers. The fun part is we learn a lot in the process.

Yep.

I love 'why' questions.

That's what makes English fascinating

Not is she funny who makes a joke. Why aren't any of you on that question like black on beans?