Prince William was "left furious" because of a slight Prince Harry and Meghan Markle included in their get-well-soon card to Kate Middleton, according to sources. Friends of Kate and William claimed that the Prince of Wales was offended at the Sussexes publicly referring to his wife as "Kate,” instead of "Catherine.”

The insiders said that William was especially angry because Harry and Meghan called his wife "Kate" when "they were sending her get well soon messages after her cancer diagnosis.” The sources said that the Sussexes’ decision to call her by that name was "an entirely unnecessary and deliberate irritation.”
It is believed that “Catherine’ is the name the Princess of Wales’ friends and family use. It is also the name William uses in private. At school and university, she was popularly known as Kate. However, shortly before her marriage to William, she made a deliberate switch to her full name.
After Kate announced her cancer diagnosis, Harry and Meghan released a statement in March, saying, “We wish health and healing for Kate and the family, and hope they are able to do so privately and in peace.”
‘William takes offence at people calling Catherine 'Kate'’
A friend of William and Kate has now said, "The fact that Harry and Meghan were unable to bring themselves to use her chosen name, even when they were sending her get-well-soon messages after her cancer diagnosis, was noted.”
{{/usCountry}}A friend of William and Kate has now said, "The fact that Harry and Meghan were unable to bring themselves to use her chosen name, even when they were sending her get-well-soon messages after her cancer diagnosis, was noted.”
{{/usCountry}}The source continued, "William takes offence at people calling Catherine 'Kate', because she has asked to be known as Catherine. It’s a fairly simple wish to respect. I’m sure Meghan wouldn’t like it if William started publicly calling her 'Meghan Markle'.”
"Of course, it’s an utterly trivial thing, but those of us who know William know that it is one of the things that pushes his buttons,” the insider added. "Pushing his buttons while he was going through his wife’s cancer seemed an entirely unnecessary and deliberate irritation. I wonder if the private card began, 'Dear Kate…'"
Another friend of the Prince and Princess of Wales said, "No one’s saying it’s responsible for all the trouble, but deliberately calling someone by a name they don’t like is just bl**dy rude. If Harry and Meghan were serious about healing their issue, a good first step would be to call her Catherine."