When you have ResizeChart set, the chart tries to calculate the title height to inflate the chart rect.
But when you have multiple lines with ttfHtml format (<br>) the title height isn't correctly calculated.

Here the code to reproduce the problem:

procedure TForm1.FormCreate(Sender: TObject);
begin
   Chart1.View3D := false;

   Chart1.AddSeries(TLineSeries).FillSampleValues;

   Chart1.BottomAxis.Title.Text := 'Line 1<BR>Line 2';
   Chart1.BottomAxis.Title.TextFormat := ttfHtml;
   Chart1.BottomAxis.Title.Transparent := false;
   Chart1.BottomAxis.ResizeChart := true;

   pTChartAxis := Chart1.CustomAxes.Add;
   pTChartAxis.Horizontal := true;
   pTChartAxis.Title.Text := 'Line 1<BR>Line 2';
   pTChartAxis.Title.TextFormat := ttfHtml;
   pTChartAxis.Title.Transparent := false;
   pTChartAxis.ResizeChart := true;

   with Chart1.AddSeries(TLineSeries) do
   begin
     FillSampleValues;
     CustomHorizAxis := pTChartAxis;
   end;
end;