Hello Rahul,
I understand your requirement is to start the successor step even if the predecessor step has failed. In your case predecessor step is Copy Plan Version which gets failed due to user locking the planning area, but successor step do not get started although you have selected event as "ALWAYS"(RED+GREEN).
Below SAP note address the similar problem. Please check if it is relevant to your SCM system.
SAP Note# 1250385 : DP Job cancellation triggers abend of the process chain
Besides please check whether status of your local chain gets updated in this table or not RSPCPROCESSLOG. It is important for status(regardless red or green) to get updated in this table so as to trigger the successor step from the meta chain. This FM RSPC_PROCESS_FINISH updates the status into this table whenever chain or any step in the process chain is finished so that it triggers next step based on the event. This FM can be run using SE37 as well.
Also as mentioned by James, This kind of issue can be handled by implementing below logic in the process chain with AND condition.
Hope this will help.
Thank you
Satish Waghmare