Euro holdings, especially ING (one of the largest holdings) are getting clobbered. NAV for fund is about the market price. So it's not that the fund is oversold. I am afraid PGF has about run it's course and since it is not actively (it's an index fund) traded, the Euro holdings will keep it down for a while. So hang if you like the divi, but bail if you can't stand some more down-side.
I am afraid that this is moving with the general market sentiment on bonds. Individual preferreds are shedding their once high evaluations and I do not know when this will stop. At some time they will become attractive to investors because many of them pay nice dividends. I think a price of $16 may be possible before it is all done.