why the drops at the front and plain at the rear?
could this be a front and back transit?
It might be an artifact from the processing so it might not be real but introduced when going from the raw data to making the light curve. The K2 data reduction is different from the original Kepler field data and since the data is noisier and has more things to correct, it wouldn't surprise me.
The feature between days 4 and 8 actually looks to be astrophyiscal, coming from the bright star near the bottom of the aperture in the image plot shown here: https://www.cfa.harvard.edu/~avanderb/k2c0/ep202085510.html
Not sure what is causing it, but it doesn't appear to be a data artifact.
The star's colours are late-K. This event happens earlier than the Jupiter crossing issue, so it's not that. It does seem to be physical, but I don't know how… it can't be a simple transit because the brightening is higher than the baseline flux, which wouldn't make much sense.
If I had to make a guess, I would say that the source is an evolved K-star and the event is an excited spot due to a stellar companion coming into periastron. But that isn't entirely satisfactory (there shouldn't be a second peak)… so formally, I don't know what this is.