This is related to my previous question here.
I'm enrolled in a MS/PhD integrated program in computer science at a South Korean university and have just started my first semester. In the linked question, I discuss my desire to quit my program, get my master's degree, and go for a PhD abroad.
The reason I want to quit is that when I first talked to my advisor in March, I told him that I noticed his lab does a lot of work that I'm interested in (NLP and finance). He told me that he'd be happy to have me and that there are "many research projects in those fields going on."
This is partially my fault, but when I entered the lab, I found out that the professor's main interest is bioinformatics, and that he's pretty much only involved with work relating to that. This is also where most of the lab's funding comes from. The fact that my professor's interests don't align with my own is more than enough for me to not want to do my PhD here.
Most of the students here, including myself, barely get any guidance from the advisor and usually teach themselves or learn from upperclassmen. I'm currently involved in a bio project that I don't want to be a part of. I've told some upperclassmen about my plans to go abroad after quitting my program midway, and they told me that there's a lot of people who are in the same boat. They said I just have to do the bare minimum to not get on my advisor's nerves and then I can do my own thing in the meantime. I was also advised to talk to the professor early on about my plans - despite having me told him twice before already - so that there aren't any misunderstandings in the future.
Is this normal? Do professors usually twist the truth to entice students into joining their lab?