High memory and swap usage caused by httpd

For some odd and random reason, if I leave my webgui open, memory and swap usage utilization is consumed 40% more until I log off webgui. It happens with all 3 browsers (IE,FF,GC) so I'm suspecting it's not a browser issue? I was looking through the raw logs for http daemon and I noticed these errors correlates with the usage graphs.

I'm using a ASG320.

Here is a slice of what is happening:
2012:11:27-08:57:11 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:11 -0500] "POST /index.plx HTTP/1.1" 200 12072
2012:11:27-08:57:17 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:16 -0500] "POST /index.plx HTTP/1.1" 200 12046
2012:11:27-08:57:22 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:22 -0500] "POST /index.plx HTTP/1.1" 200 12041
2012:11:27-08:57:27 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:27 -0500] "POST /index.plx HTTP/1.1" 200 12071
2012:11:27-08:57:32 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:32 -0500] "POST /index.plx HTTP/1.1" 200 12038
2012:11:27-08:57:38 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:37 -0500] "POST /index.plx HTTP/1.1" 200 12033
2012:11:27-08:57:43 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:43 -0500] "POST /index.plx HTTP/1.1" 200 12027
2012:11:27-08:57:48 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:48 -0500] "POST /index.plx HTTP/1.1" 200 12023
2012:11:27-08:57:54 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:53 -0500] "POST /index.plx HTTP/1.1" 200 12043
2012:11:27-08:57:59 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:57:59 -0500] "POST /index.plx HTTP/1.1" 200 12021
2012:11:27-08:58:04 x-fw httpd: 10.0.1.37 - - [27/Nov/2012:08:58:04 -0500] "POST /index.plx HTTP/1.1" 200 12053

I tried calling Sophos TS and they had no history of this type of problem.

Does anyone else have this type of issue? It doesn't happen often but I figured it might be a bug worth investigating and fixing.