I sold a rental property (TIC) in Georgia (I live in CA).

At the time of sale, based on my tentative calculation, I thought I didn't owe any taxes.
But when I asked my accountant to do taxes, he found that actually I owe taxes to GA state.
I received Form G-2RP (Withholding on Sales or Transfers of real property by Nonresidents) that states there was a loss in the transaction (based on my info).

Now, if I file a GA return and pay taxes, will I get into trouble since I said I didn't owe any taxes, initially? Would there be penalty and interest even if I pay the taxes due before 15th April. The sale date was Sep 11th 2014.