A problem with on-chip FIFO memory and NIOS II

OK, I am not sure what happens but I understand how it works...

Once the SGDMA reads out the FIFO, it gets all the data initially loaded to the FIFO, even the ones reported to have been read before SGDMA had been set up. I mean, after loading 12 words in the FIFO, its level is eight only, but the SGDMA then reads out all the 48 bytes correctly.

As if there is another data FIFO in the DMA write block, 4 words deep. According to the datasheet it should not be there, since bursting is disabled in the actual stream to memory configuration.

Cheers and thanks