When it saw what happened with the preview Galaxy Fold units that Samsung sent out, Huawei put the breaks on the release of its own foldable Mate X. After all, if your main competitor will be perfecting their foldable for five months, you would use the time to do the same and avoid the eventual bad publicity if something goes awry while you play pioneer.
It seems that Huawei has used the unforeseen release gap well, judging by a preview of the updated handset that just popped up.