problem with proxy irule

im using this irule to set up a forward proxy: https://devcentral.f5.com/codeshare/http-forward-proxy-v32 it is operational on other big-ip's i administer, but i have encountered a problem now on one of our virtual editions, with the irules being aborted: 01220009Pending rule /Common/forward_proxy_http_domain_irule aborted for :60019 -> :8080

i had this scenario on my other devices, and the solution there was to upgrade to the latest version. the virtual edition is running 11.6.1 today, which has known issues with components in the irule(table, server_closed and lb_failed).

has anyone tried rewriting the irule, or shall i just bite the bullet and plan for an upgrade?