100MB LiveUpdate downloads

I'm used to seeing the occasional 100MB download very occasionally when I run LiveUpdate.

However, in the past 3 or 4 days, I've had 3 of these very large downloads, which is very unusual.

Does anyone know if there might be a reason for this - e.g. known problems with any recent NIS updates, etc?

I have not changed my computer setup at all - it is the same as it has always been, so I can't think of a reason for this.

(I've got NIS 20.4.0.40 running under Windows 7 Home Premium 64-bit on an HP h8-1070uk desktop computer with 8GB of memory).

Many thanks.