The AXI VDMA temporarily tries to write to the incorrect addresses after receiving a size mismatch error.
For example, I am trying to write a triple frame buffer to these frame addresses: 0x617257C8, 0x3BD68950, and 0xCDD27278. The first frame comes in (VDMA starts writing to 0x617257C8) and there is a size mismatch error (fairly typical during startup conditions). When the second frame comes in, rather than starting to write to 0x3BD68950, the VDMA continues to write to the next address after the error location in the address space for the first frame. When the third frame comes in, it writes to 0x3BD68950 and gets back on track.
Often times, systems can tolerate dropping one frame, so this might not be an issue in many cases.
This is a known issue discovered in v5.02.a of the core. It is scheduled to be resolved in v5.03.a of the core (ISE 14.3 design tools).