Pinkie Pie's Ladybug Jamboree

At a music stage in Ponyville, Pinkie Pie talks with a yellow pony with reddish hair named Fiesta Flare about how no one is playing together and the performance is starting soon. They need one of Pinkie Pie's squinks and Fiesta Flare explains what this is to Tink-A-Tink-A-Too. However, a ladybug lands on Pinkie Pie's nose, causing her body and squink to fall completely off-balance and down to the floor. Cotton Candy says they're up next and asks what they call themselves. The ladybug lands on Pinkie's nose again and gives Pinkie Pie an idea that makes the others giggle with delight. Cotton Candy approves and announces their cue to come on stage to perform. The group quickly put on their ladybug outfits and begin their song. Uh-oh! Where's Fiesta Flare, Bee Bop and Tink-A-Tink-A-Too? They're  part of their band after all (left image) but has magically changed to Coconut Cream, Skywishes and (what looks to be) Triple Treat (right image)!

As a matter of fact, Fiesta Flare is next to the other yellow pony but on the left behind Rainbow Dash:

Though Cotton Candy must not have realized that there was a sudden band change because she isn't seen at all after this point but what happened to Pinkie Pie's cutie mark? It appears to have changed into someone else's (right image) when it should be like the left image (she's on the right)!

They finish and magically the original band members return while the ponies cheer.