I've tried from the example and AutoComplete never fires the LoadData event. I saw somebody else having a similar issue in the DataGrid.
<RadzenAutoComplete Placeholder="Search address..." Change=@(args => OnSearchChange(args, "AutoComplete with placeholder"))
LoadData=@OnLoadData Data=@SearchResults Style="margin-bottom: 20px">
void OnLoadData(LoadDataArgs args)
{
//console.Log($"LoadData with filter: {args.Filter}");
SearchResults = await GeocodeService.GetLocationsAsync(SearchText);
StateHasChanged();
}