@MarkDoyle
Did you have any integration configured with OPM in this scenario? If so, was it partial (event publication to UM from OPM) or full integration?
Were there any errors removing the datasource when that action was executed?
Correction of this problem will involve some deeper investigation -- Please open a case with the details of the clsuter add/remove/readd actions, error messages, and the intergration qeustion above.