Didn't know anime/manga was that formalised these days.
It's not. Some people seem to think there's some kind of "code of conduct" for picking up series that others may or may not be working on, but they are mistaken. If someone else is working on a project and someone else decides to try their hand at it, one of them will finish first, and both may be released, and fans can decide for themselves which one they think looks better/more professional. The Super Sentai scene in particular had some real ridiculousness in the past couple of years, where a bunch of people suddenly cropped up and finished subbing series that had been pristinely unsubbed for decades, and when it came down to the last handful, one of them had a group that had posted an update about a year and some change ago saying "We've got five episodes left and then we'll release a batch!" and then never responded to anyone ever again, and another series that had been started by another group three years prior and averaged one episode released every six months. One person managed to finish both and release them, and nobody gave them any trouble at all.
Frankly, if a game is not available in English (or in this case, was completely butchered), nobody has a right to "call it" or "claim it". If you wanna work on it, go right ahead, but if they think they have the right to run anyone else off of it then they're mistaken. If you're taking forever to finish and someone else more skilled/capable than you swoops in and finishes it in half the time and releases it before you're able, that's just too bad, and you can still release your version and consider it a learning experience/practice. Some ridiculous "claim" system would just lead to a bunch of projects being "claimed" by amateurs who have no skill and no hope of ever completing a project and condemning whatever title they "claimed" to years of development hell before someone decides that it's sat long enough with no updates and decides to pick it up themselves.
If you wanna translate a game, anime, manga, movie or whatever else you feel like sharing with the English-speaking world, do it. If someone else has already done it, have a crack at it and see if you can improve on it. If someone else is already working on, put your personal touch on it and share what you think is the best version. If they get butthurt because you lapped them and released it first, then they're really too touchy and overly sensitive to be taking part in the community. Half the drama caused in the fan translation community comes from some misguided notion of people having a claim on certain projects. They get all upset over criticism, or try to run off others who decide to try their skill at the same project, or pitch a hissy fit and storm off forever when people ask why it's taking years to complete yet they still decided to scare off others who might have helped or finished quicker. We really just need to realize that this community is incredibly unofficial, and if someone wants to translate something, be it already translated, never translated or in-progress, they are 100% free to do so, and nobody can tell them not to.