Interestingly, it turns out that this was not a new story - it was covered by Robert Lacey in his book about William and Harry, and picked up and published elsewhere in 2021 - in People Magazine, for example.
In that version however, Harry was not calm - he angrily refused to talk to William over the phone about the accounts that Meghan was bullying their shared staff., So feelings were high on both sides from the outset (unsurprisingly).
"Lacey's book describes an angry confrontation between the princes – first over the phone and then in person when William asked Harry about the bullying claims.
When Harry flared up in furious defense of his wife, the elder brother persisted," reads an excerpt. "Harry shut off his phone angrily, so William went to speak to him personally. The prince was horrified by what he had just been told about Meghan's alleged behavior, and he wanted to hear what Harry had to say. The showdown between the brothers was fierce and bitter."
people.com/royals/prince-william-prince-harry-had-fierce-bitter-argument-meghan-markle-bullying-claims/