ProxyPass and 10% load balancing

I'm currently trying to create an iRule that will offload 10 % of user sessions from connections to url1.testserver.com to a test pool and if any of the links on the test pool have url2.testserver.com rewrite to url1.testserver.com for client connections.

 

ProxyPass will rewrite the links. https://devcentral.f5.com/wiki/iRules.ProxyPassV10.ashx

 

And a slightly edited version of Example 3 of Ratio Load Balancing with the rand function will offload the 10% https://devcentral.f5.com/wiki/iRules.ratio_load_balancing_using_rand_function.ashx

 

The issue I am having is when combining the two as separate iRules attached to the same VIP I receive an error that says "This webpage has a redirect loop".

 

each irule seperatly works fine.

 

I suspect it due to the ProxyPass storing the default pool but a little more advanced than what I am use to so any help is appreciated.

 

Cheers