Harry isn ‘t The only royal to get a fake phone call. Years ago the queen got one from a radio host and thought he was the Canadian prime minister and told him what she was going to do to help him. I can’t remember the details.
Indeed several royals (& celebs & politicians & you-name-it) have been prank called and fallen for it.
I don't think Meghan is in on the prank. At all. It just doesn't make sense.
Because this isn't just an embarrassment for Harry, it is also an embarrassment for Meghan.
And it is a dent in their brand, which they are trying to establish.
In these early stages of brand building such an embarrassment is a big thing, much bigger than if they were established.
If Meghan were behind this, she'd be utterly reckless and sabotage her own standing and brand.
No way would she do that, ever, for anything.