What was changed on the routers during this implementation? Only configuring the module, enabling wccp 61/62 and enabling redirection on the LAN/WAN interfaces?

Were additional routes added? Is it possible a routing loop was introduced? Do you see a reasonable number of connections on the WAEs?

I suggest looking at the following to see if any problems are indicated:

On the routers:

show ip wccp - should see most packets redirected via CEF

On the WAEs:

show wccp gre - look for any high counters that don't look right

type-tail syslog.txt 50 - look for messages indicating possible problems