Bash code behaving vague: huge file processing - unix

Question

This is bit of a hadoop & unix mix issue and I'm really not sure which one's responsible for the error.
I've a bash script that performs validation of file in terms of:
Checks whether the total row count of the file matches with the value mentioned in the footer of the file. (Footer is a metadata that contains total number of actual rows above it, and it's positioned at the end of data file)
Checks whether the name of file matches with what it should be.
The function calculating row count & extracting footer count of file is:
count() {
rowCount=$(echo $(hdfs dfs -cat ${hdfspath}/${fileName} | wc -l) - 2 | bc -l)
footer=$(hdfs dfs -tail ${hdfspath}/${fileName} | tail -1)
footerRecordCount=`echo $footer | sed "s/[^0-9]//g"`
}
The code snippet calling the above function & performing validation test is below:
count()
if [[ ${footerRecordCount} -ne ${rowCount} ]]; then
echo "error=Number of records in the file doesn't match with record count value mentioned in the footer of the file" >&2
exit 1
else
fn_logMessage "Footer Record Count $footerRecordCount matched with rows count $rowCount"
fi
if [ ${fileName} -ne ${actualFileName} ]; then
echo "error=File name mismatch"
exit 1
else
echo "File name matched"
fi
The code looks fairly straighforward & simple; it is indeed and works as well perfectly.
However, the issue comes up when I started this test on huge file size (>400 GB). I receive the error as below:
Footer Record Count 00000003370000000002000082238384885577696960005044939533796567041020102349250692990597110000000000000000002222111111111111110200000003440000100013060089448361739204836173971223 matched with rows count 929901602
error=File name mismatch
Strange!!
The footer record count should actually be the number 929901602 but the number that comes up is some random number which doesn't exist anywhere in the file at all. However, even by the looks of it, it doesn't match, the output is thrown as "matched".
While the error of the next if loop is shown.
Not sure who is the culprit here, unix or hadoop. But I performed this test 3 times in a row. Every time the "Huge number" pops up is completely different from the previous one. So, there isn't even a correlation between these large numbers.
Any idea what on earth is going wrong?
PS: Like I said, the code works perfectly for small files like 20 GB, 50 GB.
Thanks in advance.