Need Help surecolor s80600 No ink dots on black prints

[GaborS101]

We are printing a black gradient on 3M IJ8150 and we noticing small point with no ink, you have to put a light behind to see it but since this is a full cover glass film we are afraid the client will reject it, we try cleaning the heads, changing the media, changing the ink, changing setting, we print this on 32 all the way down to 12 pass, same result, technician said head is firing fine, any clue?

 

[SignMeUpGraphics]

Care to share the file you're having issues with?
Or at least clip out the part that's not printing correctly.