Rarity I You Rain Cloud Man!
Fluttershy’s a Can’s Animals!
Rainbow Wat? SHUT UP!!!!!

It could mean the destiny switching spell was so powerful it would overwrite/block out any memory spells or attempts to question it. Only Friendship, the most powerful magic in the setting, was powerful enough to get them to question it enough to break the spell.

@Background Pony  
Uh, the Cakes propably thought that Fluttershy were always their apprentice\assistants, and the Apples propably thought that Pinkie Pie entered the family as a step-sister (daughter of their father’s wife\mother’s husband, because the Apple parents do not have to die the same way). Scootaloo propably thought she was a fan of Rarity, Sweetie Belle thought she was Applejack s’ sister trough marriage, and the Pie family back at the rock farm trought they only had 3 daughters (Marble, Limestone, and the much older one)

@Background Pony  
The time span was short enough that ponies might not have had a chance to start asking questions before Twilight examined her friends. Also, Rarity’s family doesn’t live with her, so they wouldn’t know that Applejack was trying to replace her until they went to visit.

@Background Pony  
Sweet Apple Acres was still intact, and Carousel Boutique was still decorated according to to Rarity’s style, which Applejack was unable to replicate.

What about the apple family and rarity’s family? Do they question why Pinkie is working in their farm or have AJ’s cm? Or why AJ works in the boutique?

Given the state of Sweet Apple Acres and Carousel Boutique, I would say the spell altered more than just their memories; it actually altered their history.

care about some exposition? let me throw I ginormous wall of text at you :D
 
https://docs.google.com/document/d/1kPodINQNRRfJA0ZOHG1xeASrNOmkdAOOAf122LuWIuo/edit?usp=sharing

@12thtimelost  
BRRRRRRRMMMMMMMMMMMMMMMMMMMMM!!!  

@12thtimelost  
Woah  
That would be one hell of a twist.

@Trickquestion  
They recognized Pinkie Pie as the comedian, and were confused by the Mane’s switching jobs. I don’t think that their memories were altered, it’s just that having some ponies switch jobs for less than a day isn’t that big a deal.
 
Besides, Twilight is the pony that they go to when magical weirdness shows up, and she started working on it right after breakfast.
 
Also, Rarity’s stint as weather pony last, what, a couple of hours? Rainbow was the second pony changed back, after all.

Rarity thinks she is the weather pony.
 
Rainbow Dash thinks she lives in Flutttershy’s cottage.
 
Fluttershy thinks she is supposed to make every pony laugh.
 
Pinkie Pie thinks she works on Applejack’s farm.
 
Applejack thinks she works in Rarity’s fashion boutique.
 

 
…and Twilight Sparkle thinks she is an Equestrian princess.

@Background Pony  
Well, OBVIOUSLY 7 hours long bubble baths render you (temporarily) immune to powerful magics. ;) This also explains why Spike has taken such long baths at other times - just to get a little peace.

I liked the episode, but I think it was waaay too much information to cram into one single episode. They should have made it a two parter.  
I wonder if our beloved show is running into budget and time constraints?

@Gentle Coltte of Leisure  
But if that were true. Why wasn’t spike affected? Twilight had immunity, because she casted the spell. But spike didn’t.

@Gentle Coltte of Leisure  
That makes sense, but if that’s what the writers intended they could have done better highlighting or implying it.

@Trickquestion  
I think, because she altered something as powerful as the elements of harmony, it had a proxy effect on everyone that came in contact with the mane six.

Not JUST their memory.
 
Alternatively, its not their memories, as in the memories don’t belong to them.

What seemed off to me is that none of the villagers seemed to realize something was wrong, they just instantly turned hostile when the Elements started doing the wrong job poorly. Weird shit happens in Ponyville all the time, so did no one come to the realization something was wrong? Or did they just think the Mane Six had collectively decided to troll the entire town on a whim and weren’t going to take that shit?

she meant it was not just their memory, so their is no plothole here