Her problem is that she's just a terrible actor. I don't just mean among other actors, but people in general. Every encounter with anyone just looks so false, so affected, and the results are awkward.
I think I'm one of the few people who saw the video of her in Africa, when the poor young woman was telling her about her child dying. She said 'He died', and Meghan turned her head away, and the woman thought she mustn't have understood (because how could anyone, especially a new mother, react with such indifference), so she said 'He passed away'. Meghan looked at her impatiently, then sat on the floor to play with the babies/toddlers with a big smile, while looking for the camera. The bereaved woman looked crestfallen and utterly bewildered.
I think that was the real Meghan, the Meghan that the royal family and ex friends and family got, the Meghan that her staff get. The on camera version is just so obviously phony that it's hard for those of us that see it to understand those that don't.
And then there's incidents like the wine and no licence, she just fumbles every single bag. It's difficult not to find it amusing once you've seen through her.