Filling opacity affects plot image resolution

Question

Using v.13.3

I have a list of predefined colours that I tend to use for my own plots and found out that if you apply an opacity condition to the filling between two functions using a predefined colour, then the entire resolution drops if the Opacity is below 0.5.

ListLinePlot[{Table[{x, Sin[2 \[Pi] 4 x] + 0.5}, {x, 0, 1, 0.001}], 
    Table[{x, Sin[2 \[Pi] 4 x] - 0.5}, {x, 0, 1, 0.001}]}, 
   Filling -> {1 -> {2}}, PlotStyle -> {Opacity[0]}, 
   FillingStyle -> Directive@{#, Opacity[0.1]}] & /@ {Red, 
  RGBColor @@ {0.741176`, 0.0156863`, 0.160784`}}

I am not certain if you can see it, but the frame ticks appear to have a lower resolution on my screen.

The weirdest is that if you use Show to have multiple plots together, then the other plots are also affected in resolution.

Show[{ListLinePlot[{Table[{x, Sin[2 \[Pi] 4 x] + 0.5}, {x, 0, 1, 
        0.001}], 
      Table[{x, Sin[2 \[Pi] 4 x] - 0.5}, {x, 0, 1, 0.001}]}, 
     Filling -> {1 -> {2}}, PlotStyle -> {Opacity[0]}, 
     FillingStyle -> Directive@{#, Opacity[0.1]}, ImageSize -> 500, 
     FrameStyle -> Directive[Black, 22]], 
    ListPlot[Table[{x, Sin[2 \[Pi] 4 x]}, {x, 0, 1, 0.01}], 
     PlotMarkers -> {"OpenMarkers", 10}]}] & /@ {Red, 
  RGBColor @@ {0.741176`, 0.0156863`, 0.160784`}}

Does anyone know why is the threshold close to 0.5 for Opacity? And why does this bug work only with custom colours?