Client accessing both redirect and default pool in irule.

First thing, you can probably streamline the iRule a little bit:

when HTTP_REQUEST { 
    switch -glob [HTTP::uri] { 
        "/foo/bar/_*" - 
        "/foo/baa/_*" { 
            snat automap
            pool redirect-443 
        } 
        default { 
            SSL::disable serverside
            pool default-80 
        } 
    } 
} 

Second thing is that it now depends on HOW it's failing. For instance, you left out the rest of the snat command in your sample code, so assuming you were pointing to Automap or a specific snat pool. Do you intend to not apply a snat for default pool traffic? What does the redirect look like?