Hi Satwik,
The problem is, that when you try to verify the data after the second adc_capture, the cpu will give you a cached value, instead of the value from the specified memory space.
Try to flush the cache after every adc_capture(), using the function: Xil_DCacheFlush(). This should resolve your problem.
I also pushed a patch for this issue, so if you update your repo, should be enough.
Thanks,
Istvan