DMA issue with memory overlap between 0x800 and 0x10800

We've noticed an issue with the Piccolo in which we have a DMA buffer for the McBSP set up around 0x10800 in memory. The values were good in the DMA buffer but showed up corrupted in the McBSP TX register. We discovered through experimentation that the value in the McBSP TX register was actually the logical OR of the value in the DMA buffer at 0x108xx and the ADC results register and 0x8xx. We solved the problem by forcing the DMA buffer into a different location in memory. I'm wondering if this is a known issue or if there is any configuration option that we might have missed with regard to running both the DMA and the ADC.