(full disclosure, I haven't read the chapter, and I'm replying under the assumption that it is actually chapter 49, and not just a troll chapter)
This is hardly the first time I've seen a sniper pop out of nowhere and release their own translation of a chapter far ahead of where the previous group left off. There must be some underlying cause for this to keep happening on different series by different group.
Can someone with more insight into the translating community explain why this keeps happening? I can't for the life of me piece together a logical explanation, but then again, I'm hardly the most informed on the topic.