The fhirpath and xpath expression in nsd-1 do not express the same thing:

<constraint>
<key value="nsd-1"/>
<severity value="error"/>
<human value="Root systems cannot have uuid identifiers"/>
<expression value="kind != 'root' or uniqueId.type = 'uuid'"/>
<xpath value="not(f:kind/@value='root' and f:uniqueId/f:type/@value='uuid')"/>
</constraint>

Please update to: kind != 'root' or uniqueId.type != 'uuid'