Why am I receiving the 'Objects are already being edited' warning message when trying to make changes to custom objects?

Environment:

Custom Objects (CO)
Oracle B2C Service, All versions

Issue:

When I open the Object designer, I see this warning:

Objects are already being edited

<name> has been editing this data since <date time>

If you are sure they are no longer editing this data, you may claim the lock for yourself. Doing so will prevent them from saving their uncommitted changes.

Do you wish to override this lock?

Resolution:

If you open the Object designer and see this warning message, this does not mean there is any kind of issue with your deployments. This is a simple warning that somebody else is already editing custom objects at this time. 

If you would like, you can override the 'lock' by clicking 'Yes' to the warning.  Only do so if you are sure the other account is no longer actually editing custom objects or their edits could be lost.