Unless the claim comes with a LWP version number and/or specific indications as of where the truncation would take place, I doubt that. I've used LWP to transfer large files, and never have encountered truncation problems that were inherent to HTTP::Message or HTTP::Response.

Note that the whole response tends to get stored in memory. So for large downloads you should consider using the :content_filename or the :content_callback argument to directly save the response content.

If you truly believe that it's not your network connection, a proxy or anything else interfering, you will need to get a network sniffer (like Wireshark) and look at the differences between a transfer that works (without LWP::UserAgent) and the transfer that breaks (with LWP::UserAgent).