Strange HTTP Proxy issue both 2.2rc2 and 2.2 28 May 09 release

I've had efw 2.2rc2 running since its release and until today have had NO problems.  I have it configured with multiple uplinks on red, green+blue+orange.  Today, with 2.2rc2 running, client browsing became extremely slow and at times would time out.  I tried disabling uplinks one at a time to rule out the possibility they were having issues.  Finally I disabled the HTTP proxy and clients started browsing as normal.  There has been NO changes to the configuration in many months.  Enabling the HTTP proxy again caused problems.

I swapped the box and performed a fresh install of the current 2.2 release.  After manually configuring to match the other box and restarting all modems and the efw box, I was browsing fine until I enabled the HTTP proxy.

What could cause this strange problem?  What can I do to resolve the issue?