Well, unless you are very temperamental an episode like this doesn't just pop out of the blue. There has to be some underlying tensions to trigger it.
Otherwise you would normally discuss any disagreement afterwards in private.
Three things springs to mind.
A) The girls are very uncomfortable with being in the public gaze and with posing. There are periods in the life of children where they are very aware of themselves and how they look in the eyes of others.
The perfect "torture" for say a 13 year old boy is if his mother gives him a big hug in front of his friends - worse if it's in front of girls - give him a kiss and call him "sugar-cube".
- Even if they actually like getting a hug from time to time - in private...
The same thing applies for girls.
Queen Letizia knowing this may have reacted instinctively and ferociously in order to shield her children from embarrassment.
We can discuss whether that is justified or not. And also whether that would be the right approach.
Queen Sofia may have considered this no be no big deal, and after all the girls have to get used to being in the public glare, and they were safe surrounded by their family. And as such she reacted with anger, and grabbed hold of Leonor's arm.
- So to sum up this may have been a clash about how to bring up children the right way and not least protecting them - and I think all parents have been there.
B) Queen Sofia is genuinely fond of her granddaughters. No doubt proud as well and would like to pose with them and show them off - and the PR ain't bad either...
Perhaps to the extent that it's too much for the girls. So Letizia may have reacted with a: "Will you back off!! Good grief!!"
C) Or it's simply a deep-rooted disagreement in how to expose, prepare, and train the girls to approach the public.
Queen Sofia perhaps believes she is the one who knows what she is talking about, having been in the public glare for all her life actually and raised children of her own in the public light.
While Queen Letizia, with her background in the media, believes
she is the one in the know.
So it's basically: "They are
my children and
I decide how to prepare them!" Versus: "You don't know what you are talking about, you silly... How many years have you been royal anyway?"
- I think you get the drift. ?
Whatever, King Felipe was sure taken aback and rushed in to intervene.
And the girls, well, no matter how fond they may be of their grandmother, you cannot expect a child at that age to side against her mother.