Orchestrator using same Robot Key for multiple machines

Apparently when some added robots to our Orchestrator, he tabbed the “Create another” for creating multiple robots. But he created them on different machines and not in the same machines. Now our Orchestrator have 3 robots in different machines with the same robot key and it cant be edited or changed. I tried to delete the robot from Orchestrator and add it again but it automatically fill the Key* field with the same key that was used before.

This situation causes that when we updated the Orchestrator from 2017.1 to 2018.2. All the robots started running on the same machine but with different usernames and we had to delete them from Orchestrator and then add them again.

How can I get Orchestrator to generate a new Key for the robots and stop using the same on every machine.