Fix the problem mentioned here: https://root-forum.cern.ch/t/weird-behaviour-since-root-6-18 A simpler reproducer is:
Fix the problem mentioned here: https://root-forum.cern.ch/t/weird-behaviour-since-root-6-18
A simpler reproducer is:

{
   TCanvas *C = new TCanvas("C", "C",0,45,800,800);
   C->SetLogy();
   Double_t X[5] = { -11.0, -10.5, -10.0, -9.5, -9.0, };
   Double_t Y[5] = { 0.0000, 0.0080, 0.0085, 0.0090, 0.0095, };
   TGraph *graph = new TGraph(5,X,Y);
   graph->Draw("al*");
}

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