My manufacturer is asking me to remove those lines from the ground gerber layer

[![Gerber ground plane problem][1]][1]

The design was made in eagle, I've been searching information about this problem and I've found nothing, I don't know if it has a specific name or it isn't a real problem

It's a problem of the gerber file?

I'm using Gerbv 2.6 to visualize the layers and depending on the zoom of the images, the lines appear and disappear


  [1]: https://i.sstatic.net/gBS43.png