Hi Khan,
Even though the data load to Lookup DSO gets complete may be the activation step takes time to get complete. If mean while Target DSO load started it will fail since the activation of Lookup DSO is still in progress.
Here you can do one thing to avoid the issue as both are in different Local chains - Check out the impact of loads and change the design of the meta chain such a way that, First Lookup DSO load and activation Local chain completes then link Target DSO local chain. This is the way you can avoid the issue.
Regards,
Srinivas Vetcha