Have you ever got an ugly uneven solder mask on JLCPCB black panels? In the last order I got this unpleasant surprise where 5 out of 15 black ENIG boards (to be used as front panels) have this noticeable imperfections (see pictures below), as if the coating has thickened unevenly on the surface. It is much more visible in real life than in photos, since the uneven areas reflect light very differently, highlighting the defect.  Other pictures: [https://imgur.com/a/TFUSXi8](https://imgur.com/a/TFUSXi8)<br> <br> I sent a quality complaint, they replied apologizing and saying that it's a general problem in the "exposure process" for black boards, and that they will try to find a way to reduce this issue and improve the quality control next time. The other 10 black boards in the same order are fine, like all the ones in my previous order, and it's not nuances: either the solder mask is completely defective, or it isn't at all... They gave me a partial refund for this time only, but warned me that they can't make sure it won't happen again: I get it, anyway I want to ask how many of you had similar issues, to get an idea of how common it is. Thanks.