In some cases if using formula fields (especially as labels) the search fails.
Workaround can be to define the datamanagerSearchFields annotation and explicitely define the search fields, including a formula label field (which works fine).
However it fails if defining an FK property (which itself has a formula label on it) and not explicitely defining the label.
If fk_name.label is a formula field then:
fk_name.label defined in datamanagerSearchFields works where as
fk_name defined in datamanagerSearchFields does not.
Ideally it would not be required to define the formula fields at all and it would work out-of-the-box.