Honestly, I don't understand why some people so strongly dislike Jaye. Her actions and behaviour are pretty understandable in context. She's not perfect, but that's kind of the point. The characters are meant to be real, complex and messy and so far I think the story has delivered on it. Perhaps it's some holdover from earlier chapters where people assumed the worst and became entrenched, I don't know.
To go on aside, I think at least part of the issue is the unique, interactive nature of narratives in visual novels, or video games more generally. Because players play an active role in constructing the narrative, they can therefore increasing interpret the narrative into how they want to play.
To use an video game example, consider Yennefer vs Triss in the Witcher 3. A lot of players already have some preconceptions on who they prefer, either from the books, previous games, or even just first appearances in the game itself. When it comes to make decisions in the game, you can reinforce that preconception and shape the narrative. If you believe Yennefer is Geralt's only and true love, then you're going to pick all the positive dialogue with Yennefer and be standoffish with Triss. Geralt's positive response to Yennefer confirms the narrative that Geralt still loves Yen. Conversely, if you think Geralt has move pass Yennefer and loves Triss, you're going to pick all the dialogue where Geralt gets annoyed at Yennefer. Therefore Geralt's negative response confirms the narrative that Geralt has gotten sick of Yennefer's cold and invasive personality.
To bring it back to Chasing Sunsets, I think a similar effect has occurred with Jaye. The confrontation with Christian on the yacht is probably the best example. If you dislike Jaye, then you probably think Jaye is vindictive and petty, or was trying to spite MC by bring Christian on the yacht. Therefore you would pick the "not getting involved in this option". This option seemingly confirms that narrative that Jaye is being spiteful, as MC walks away in disgust.
Conversely, if you like Jaye, then you probably think that Jaye was attempting to use Christian as an "ice-breaker" so to speak. Getting MC to "defend" Jaye again as a means to remind each other of their bond and potentially to renew it. If you pick any of the three "good" options, the narrative seemingly confirms this too, as Jaye and MC hug and embrace after it - Jaye's plan worked.
You can apply this to other decisions too, including following response to the hug. What ends up happening is that different players are experiencing different narratives - the Jaye in one player's narrative is a different Jaye to another player's narrative.
Though I don't think this is the only reason why people might dislike Jaye, I think it's a contributing factor. As for Jaye's other specific actions:
Reading her brother's journal is super understandable. Yes it's an invasion of privacy and hypocrtical, but honestly, can you blame her? She's just been reunited for her estranged and beloved brother, who has done some crazy stuff while gone, and only left because of huge miscommunication. Wouldn't you be tempted to know what they were thinking at the time?
For the general miscommunication and standoffishness when they were teens, I really envy you people whose experiences with teenage romance were only positive and problem-free. Teenage love is extremely messy and prone to big errors, let alone the familial circumstance Jaye and MC are in. I find the love between Jaye and MC extremely believable and sympathetic, and why I find the game so far compelling.
I can't remember what other major complaints about Jaye there are.
