3.0.0 (serenity) - datatable rowGroupMode="rowspan" initial render sort not by <Column> sortFunction

[marcov]

On first render a datatable using a specific sortFunction in <Column> does not sort using the custom sort function.
Anyway it sort at once the wrong way, confusing the original order of "value" prop content.
Successives reorder (by click on column header) work right.

Other props:
value={this.righe}
rowGroupMode="rowspan"
sortField="data"
sortOrder={-1}

<Column field="data" header="Data" sortable={true} sortFunction={(e) => this.righe.sort((a,b) => (a.progr - b.progr) * e.order)}/>


Any Hints ?
Tnx!