SN does not allow me to back out my update set in test instance because it not safe to do so

[bbf3562]

After promoted my update set from development instance to test instance, I tested it and found some mistakes. I wanted to back out my update set in test instance but the SN system prevent me from doing it and it display error message, "This version will not be backed out because the system has decided that this it is not safe to do so. This is a system record and there is no previous version to back out to.". Then the system auto generate new update set Default with my update works.

 Here is the status that my update set failed to back out even though it said Backed out,

Here a screenshot that SN auto generate Default update set after "failed" to back out my update set,

Does anyone had this before and how to solve that? All I wanted is to back out my update set.

[Brian Lancaster]

I have never see this before but I have always found it best practice to not back out update sets.  Instead of would suggest creating a new update set in dev fix the issues and then promote that to test.  When you are ready you can then merge the update sets and move the newly created one into prod.