Found out the answer that since we NOT ONLY changed the data in a table within the tablespace BUT we also created another table within the tablespace past the last backup (incremental delta) whichh thus the Catalog was changed, the info displayed in a list tablespaces show detail, Minimum recovery time, shows that the "timestamp" is past the last backup. So it looks like DB2 is doing a restore but it can't.
It would have been nice had we seen some informational "warning" that a restore couldn't be done.