What version of SRM do you have in your environment?
I found the following in SRM 5.1.1 release notes:
Custom recovery steps do not stop virtual machines from powering on before IP customization.
If you insert a custom recovery step after the "create writable storage snapshot" step in a test recovery or after the "change recovery site storage to writable" step in a real recovery, and if you have configured the virtual machine for IP customization, the recovery plan does not wait for the custom recovery step to complete before powering on the virtual machine. This has been fixed.
Do you use IP customization?
Michael.