I'm asking in general, but here's my story specifically:
The company culture is great. My co-workers are all extremely talented people that I've learned a lot of good practices from. The company has a great reputation. Management likes me and has gone out of their way to make me feel welcome. This is my first full time job and I've been here for a little under six months. I have good internship experience from before this but no real open-source work to show. Leaving the company this soon would probably burn some bridges no matter how gently I did it. There’s an unwritten expectation that you stay for at least two years.
The main reason I want to leave is that the work itself ended up being much more simplistic than I thought it would be when I first took the job. Simpler than what I was doing previously as an intern at another company. I feel like I'm wasting months doing really trivial work and that it's going to hurt my chances of getting more interesting work later on. My current assignment is a CRUD front-end only app using an outdated framework that I was already proficient in before I started working here. I won't be able to get a new assignment for another 4-9 months, and my next assignment isn't guaranteed to be anything more interesting. Pay is slightly below average for my area, and benefits are extremely poor by any standard.
I wouldn’t worry about perception, especially in software. Moving after 6 months multiple times would be bad, but moving a few times in your first four or five years isn’t a big deal. I think the opposite actually applies in software, staying at someplace too long can be seen as a red flag if it’s not a top notch company using cutting edge tech.
The real risk though is leaving a good company culture with good management and a good team. Places with both are probably fewer and farther between then you would imagine. You may find better pay working on cutting edge tech with awful management and egotistically, unhelpful teammates, especially at some hyper growth companies.
The answer depends on what you want and it sounds like more interesting work is important. If there is no way to get your ‘simplistic’ work done and do interesting stuff on your own or helping another team, then moving is probably worth it. I do wonder though if the place is so great and your coworkers so talented, why is the work so simplistic? Is it a lifestyle company or are you missing something without the experience to know?
In any event, think about what you want, take your time and do research if you choose to move, and best of luck in your career.