pt-query-digest on tcpdump with blobs


I have tcpdump running on three servers with this command line:
/usr/sbin/tcpdump -s 65535 -x -nn -q -tttt -i bond0 -c 600000 port 3306 > FILE.txt

Then I use pt-query-digest --type tcpdump FILE.txt to parse the tcpdump files. All files are parsed by pt-query-digest on the same separate server.
What I have discovered is that on two of the servers (running 5.6.17) the pt-query-digest works just fine. On the one running 5.5.29 I get the following errors when trying to run pt-query-digest on the file:

Will retry pipeline process 3 (MySQLProtocolParser) 1 more time.
The pipeline caused an error: Pipeline process 4 (MySQLProtocolParser) caused an error: Argument "" isn't numeric in substr at /usr/bin/pt-query-digest line 4513, <> line 185450.
Terminating pipeline because process 3 (MySQLProtocolParser) caused too many errors.

Line 4513 is:

elsif ( $first_byte == 252 ) {

And this leads me to the conclusion that its something caused by blobs in the tcpdump file. It makes sense because on the two servers that work we have no blobs in the databases.

Any suggestions on how to fix this or is it just a bug?