Refer to this article to see an overview of scheduled license change logs
If a scheduled license change log (slcl) fails to update a subscription, the slcl will result in a “Merge Failed” status reason as shown below.
This means that the job which ran to update the subscription also failed. To learn the failure reason of the subscription update, open the Work 365 Job on the job tab.
Then look at the failure reason listed under the Parameters tab of the job.  
Resolve the issue based on the error message. Refer to this guide on resolving failed license change logs.