This thread talks about why some of us do not decimate and a solution for the ones that did decimate, the pxgeek post smoothing option comment.So you'll just have to smooth the exported decimated mesh causing this issue for you and all should be fine, it not post results.The lazy and probably shouldn't be used solution is…
I made a high poly mesh in ZBrush and decimated it. but after baking it, it leaves this weird low poly cluster. Tris: 3mil Low poly is already smooth if anyone can fix it, I would appreciate it a lot! Thanks