You don't drop a bomb like that just to walk it back the next movie, "just kidding!"
Especially when the movie has a largely unnecessary scene that reminds us ...
Albus has a sister whom he didn't "love enough." No mention of his brother. Not sure if Credence is a transmorgified version of the sister or her son or what, but that scene makes it pretty clear she's the key to the story.
...
In general, this movie is definitely polarizing. Anecdotally, it seems to me Millennials who grew up with the books are far less forgiving of it than those of use who read the books as adults. I have to believe this reflects a disillusionment with JK Rowling in general, if not society itself. The number of fans who want to quibble whether a certain cameo character should be old enough to be a teacher seems an unreasonable standard to judge when you remember the original books have time-turner-sized plot holes.