real time data display problem

[kdxq]

I used imgui and implot for real-time display of temporal data and found the following problem:

When a series of data values remain constant (the bool variable is most pronounced and often remains in a state), after a few hours, the curve no longer displays. picture as follow

Some of the codes are as follows:

if (ImPlot::BeginPlot("",ImVec2(-1,0),ImPlotFlags_NoMenus) ){ ImPlot::SetupAxisScale(ImAxis_X1, ImPlotScale_Time);

					if (i == rows - 1)
					{
						ImPlot::SetupAxes("", NULL, flags_axis, flags_axis);
					}
					else {
						ImPlot::SetupAxes("", NULL, flags_axis | ImPlotAxisFlags_NoTickLabels, flags_axis);
					}

					for (int k = 0; k <= pltManager.pltVec[i].yMax; k++)
					{
						ImPlot::SetupAxis(ImAxis_Y1 + k, "", flags_axis);
					}

					ImPlot::SetupAxisLimits(ImAxis_X1, t - history, t, paused ? ImGuiCond_Once : ImGuiCond_Always);
					ImPlot::SetupAxisLimits(ImAxis_Y1, 0, 1);
					ImPlot::SetNextFillStyle(IMPLOT_AUTO_COL, 0.5f);

					

					if (pltManager.pltVec.size() > 0)
					{
						for (int n = 0; n < pltManager.pltVec[i].plt.size(); n++)
						{
							
							int k = pltManager.pltVec[i].plt[n].lineIndex;


							if (vecPltItem[k].isBIT)
							{
								ImPlot::SetupAxisLimits(ImAxis_Y1, 0, 1, ImGuiCond_Always);
							}
							else {
								ImPlot::SetupAxisLimits(ImAxis_Y1, 0, 1);
							}


							ImPlot::SetAxis(pltManager.pltVec[i].plt[n].yIndex);
							ImPlot::SetNextLineStyle(vecPltItem[k].Color);
						
							if (vecPltItem[k].buffer.Data.size() == 0) continue;

						
							if (vecPltItem[k].isBIT)
							{
								ImPlot::PlotDigital(
									&vecPltItem[k].Label[0],
									&vecPltItem[k].buffer.Data[0].x,
									&vecPltItem[k].buffer.Data[0].y,
									vecPltItem[k].buffer.Data.size(),
									0,
									vecPltItem[k].buffer.Offset,
									2 * sizeof(double));
							}
							else {
								ImPlot::PlotLine(
									&vecPltItem[k].Label[0],
									&vecPltItem[k].buffer.Data[0].x,
									&vecPltItem[k].buffer.Data[0].y,
									vecPltItem[k].buffer.Data.size(),
									0,
									vecPltItem[k].buffer.Offset,
									2 * sizeof(double));
							}

Please help me see how to troubleshoot this problem?