Weird error in gnuradio block related to gr.file_source

Hi,
I am confused with the error that I am having in my block.

I have two files that I use for testing the gnuradio block that I am
developing. The input (type gr_complex) to the block is a gr.file_source
and
I use 4092 input_items that I store in a buffer to work in the
general_work
function. In order to make sure that I was reading the files correctly
and
storing the input items in the buffer properly I did a file write
operation
using (fopen, fwrite) and write the input read in the block into a
binary
file. Later I compare the input file and the newly written file
expecting
them to be the same. Strangely, when I use the first test file I have no
problem but when using the second test file the later half of the data
is
not the same. Half of the data in the newly written file doesn’t match
the
data in the input file used.

I am utterly confused. Can someone help me out here?

Thanks
John