How do you define "stable"? If your testing has shown that it supports your use cases, your environmental conditions and handles your load then it is stable from your perspective.
Would you mind providing some details (forums or email) about your expectations?
I have found a problem with instances of processes. When I start multiple instance of same process, JMSIntegrationService mix the instances inside the Token variable. Two instances started at the same time and in one instance flow did not continue and other instance activity is mixed with current instance process. I have overridden the JmsIntegrationService to get invokes for each activity to handle. Take the token's process instance id and see the problem. Can Jbpm BPEL work with multiple process instances at the same time? It is very important problem I think? Can anyone tried to handle multiple process instances?
Thansk a lot.
Do your multiple-instance problems happen even when you use correlations?