This is an occasional occurrence with all the VSCO Film packs, but it is more prevalent with 04 than 01-03. The reason is that the films emulated in 04 have some pretty extreme characteristics. To match these looks, we were required to apply some pretty extreme adjustments, and occasionally this can cause some artifacts. To combat this, we made sure that the biggest changes were happening in places where you can make changes yourself, rather than the profiles. Generally, you can almost be certain that the problem is coming from the HSL Tool, located right below curves in the Develop Panel. An easy way to check whether this tool is causing the problem is to simply turn it off completely using the switch at the top left. If your problem goes away by turning off the HSL tool, you know it's something in there. Before we explain how to go about fixing a photo with these artifacts, let us explain what's happening here.
To turn "off" the HSL Tool, simply click the small box on the top left hand corner. All of the sliders should turn grey to indicate it is "off"
This problem shows up most often in smooth, blurry backgrounds where there is a gradual transition from one color to another. Most likely, you're seeing some weird lines in the bokeh of a photo right around where two colors intersect. What's happening is that one color is being pushed in one direction, while the other color is being pushed in the opposite direction. Where the two colors meet, you have a transition between these push/pull adjustments and a line effect sometimes appears where one ends and the other begins.
So, to fix one of these artifacts, we need to find which two colors are getting the push/pull adjustments and adjust them in the HSL tool. In Film 04, Blues, Reds, Magentas and occasionally Greens are getting the heaviest changes, so it's worth looking there first. If you see a large negative or positive number around one of your offending colors (most likely in the Luminance section) try pulling those sliders towards 0 until you see your artifact disappear. For Blues, there is also the new Blues toolkit items in the color portion of the toolkit that can make this adjustment quicker.
Be sure to watch this great walkthrough video on VSCO Film 04 here: http://vsco.co/blog/vsco-film-04-walkthrough-video.