I heard an interview with Emily Andrews, who writes for one of the tabloids (The Sun). The interview was before H&M's return to the UK in March, when they were in Canada. She said at that time that their desire was always to be in the UK, and her sources said they were in Canada because they were "offered a free mansion" there.
She also said she'd been told by an insider that there was a rift between William and Harry, centred mostly around William (who is more cautious) advising Harry to take things more slowly. She said there was no rift between Kate and Meghan. I suspect that information is accurate, as it's been widely reported, but there may be other things behind it, given family dynamics. Of course, if MM heard that, and depending on how it was presented ("William doesn't want me to marry you" as opposed to "William is cautious by nature and said I should wait a year before marrying."), that likely would colour MM's feelings toward William as well.