When printing a white solid area, there are always gaps in the print. This can result from the white channel settings in the Print Environment. This usually happens with inks that dry quickly on the print media and only have a low dot gain.
Note: Of course, this works for Finish/Varnish und Midlayer channels. If you have multiple channels, these steps must be performed for each channel.
Note: These setting can then be saved as Image Preset.