
Mr Red Prince seemed fine and dandy with being future engaged to princess since the one he wants to mess with is just a maid and can get to her whenever.
But since that maid is now here and not dressed like a maid, he must get her before being engaged.
In other words, consorting with the help is acceptable as long as you're royalty, unless you're consorting with a high status holder, then you will be ruined.
Go Duke, ruin his face!

Originally there were 2 people working on the webtoon (seen on title pages of ch 1-10) then only 1 person after that.
Whether or not it's the same artist (Lee Oh vs. io), I will surmise that some cuts were made to accommodate the artist. Which ultimately means that her mouth details ended up on the chopping block.
You are now looking at Ms Potato Head with the "Oh" mouth.
Ally? Alice? A-hole? is getting anxious and more impatient since Eve became skinny. She knows Lex is starting to slip away from her.
She was complacent when Eve was fat because Lex never showed interest in his short & obese fiancé. She believed that Lex would marry her so there was no need to worry. Now she doesn't know what to do and her actions reflect that.
But to expect the engaged prince to publicly show favor to someone that is not his fiancé is stupid. Even bragging about her future higher status.