I have been trying to find out what manga the image for this credits page is from forever but I have given up... hopefully a kind nufian can help me out. I have checked through LHtranslatioms catalog so unless I mised it its not on their site at least
Most scanlation groups either use a character from their manga, a stitch of multiple characters, or take drawings from pixiv / draw their own stuff. That has a bunch of colored characters that look stitched, so they probably drew their own. Especially since you say it's none of their series.
looks like it's stitched from two different artists do I'd ask them where the images came from, if they respond