The jumpbox.com website seems to be sending multiple copies of files in certain circumstances.

The problem seems to occur in the following circumstances.

I click on the Library link.
I then click on the Download link for a particular Jumpbox (the link that says either Subscriber or Free).
I then click on the Subscriber Download button of the free equivalent.
If this is the first file I am downloading in the session, I log in with my normal credentials.
The download starts.
The website then returns me to the first page in the Library.
If I then click on the link for an earlier page in the Library (say 2 when I am on page 1), I am taken to that page but, at the same time, another copy of the file I previously chose will start to download. This can happen several times.

This has happened the last few times I have downloaded from the Library. It does not happen with any other website.

I am using Safari Version 4.0.4 (6531.21.10) running in OSX 10.6.2 on an 8 core early 2008 MacPro with 10 GB RAM.

This is more an inconvenience than a real problem but I can't think of anything at my end that could be causing this to occur.