According to the chart from google. This fund is down 7% for three months, but looking over to the right it shows this fund is up 7% ?
So what is the truth?
Scroll down to the "Dividend and Capital Gains Distributions" section of that page on morningstar. You will see there was a distribution (i.e., payout from the fund) on 12/06/17 corresponding to the sudden drop in value. The payout resulted in a drop in capital in the fund, reflected by the loss in value. However since a distribution is paid out to the investors, it does not result in a loss to the investor.
So, assuming your estimates are correct, it's perfectly normal for the NAV (Net Asset Value) in a fund to be down ~7%, but the total return to be up ~%7 such as in this case. They're both the truth!
This fund paid out a dividend of $4.177 on December 6. Any time a dividend is paid out, the price of a fund or stock should fall by the amount of the dividend, but this is not the same thing as a loss.
Normally we compute returns as follows:
R = (End Price + Dividend)/(Begin Price) - 1
so that the returns will not show the stock down when a dividend is paid. This corresponds to the wealth change in an investor and if you do this each time a dividend is paid, then the returns you compute will correspond to what an investor who is reinvesting dividends will get.
Often data providers will give you the "adjusted price," which is a theoretical price series that would give the right returns without you having to put the dividends back in. This is the norm for mutual fund reporting since most funds reinvest their dividends. However, the chart you have included is the raw price per share, so it will drop any time there is a dividend (apparently once a year, for this fund).