blat process freezing intermittently

I use blat in FTP scripts at my job to mail back the log output. I haven't
had any problems for years until recently some scripts are freezing when
blat is executed. This happens intermittently with different scripts at
different times. It only happens a few times a week over several hundred
job runs. I've added the debug parameters to troubleshoot the problem but
I'm not getting any useful information. When this happens I kill the blat
process and the script finishes. It's running on 64-bit Windows 7
Enterprise OS. Here is an example of the debug log:


blat tmpfile -s "subject" -t "recipient" -log debugfile -debug -timestamp


2017.03.28 12:30:12 (Tue)------------Start of Session-----------------
Blat v3.1.2 (build : Dec 27 2013 14:33:12)
32-bit Windows, Full, Unicode


I verified debug output is correct on a successful run. I haven't upgraded
blat yet because I'm hoping to know the root cause of the issue first. Can
someone recommend next troubleshooting steps?