The workaround is to use Universal session persistence instead of Monitor application cookie. Universal session persistence uses data supplied to the pool by the 'connection.setPersistenceKey()' TrafficScript as a key to identify which session the request is in.
Rule session maps are shared by all traffic managers in a cluster, so requests received by different traffic managers will apply the same sessions.
To use this workaround, the vTM license needs to have support for 'universal' session persistence. You can verify this by clicking the System > Licenses > Features, and make sure 'universal' is listed in the Persistence types.
Persistence types supported are: asp,ip,j2ee,kipper,named,sardine,ssl,universal,x-zeus
The license also needs to have support for TrafficScript. Both 'Advanced' and 'Enterprise' licenses have support for TrafficScript functionality.
To implement the workaround,
1. Create a Request Rule and add the following line (replace the PHPSESSIONID with the actual cookie name)
2. Then create a Response Rule with the following line;