Rule Reading SSLCipher Not working

I see the problem now. It has to do with the way you have specified the header insert command. When you only use one argument, the command assumes there might be multiple headers you are inserting as a list.

Try using this form instead:

HTTP::header insert "SSLClientCipher" "[SSL::cipher name], version=[SSL::cipher version], bits=[SSL::cipher bits]"

Notice that I broke the header name and the value into separate arguments. This will better identify what the header name is and what the header value is.