nx_packet_data_extract_offset() says it's extracting more bytes than I'm telling it to extract

I have received a packet of 1124 bytes.  I'm passing a buffer of 1024 bytes and telling nx_packet_data_extract_offset() to only extract 1024 bytes.  It returns, in bytes_copied, 1124 bytes.  It is overwriting the buffer I am passing in.  This seems like a definite bug to me.  Are others seeing this behavior?