bigip.conf won't load due to invalid requested attribute

I inherited a production configuration. The top of bigip.conf is:

datastor {
   low water mark 80
   high water mark 90
}
deduplication {}
shell write partition Common

v10 b verify load returns:

The requested attribute (deduplication {) is invalid for 'datastor'.

A similar but different bigip.conf, with the same beginning lines does not return this error. Is this a false positive? Is there a recommended way to troubleshoot?