Mathematica front-end code alignment issue

I am having a frustrating recurring issue with the frontend (Mathematica 12.1.1 for Mac OS X x86 (64-bit) (June 19, 2020)).

I will have a notebook which works just fine, all lines evaluate. Next, I will close the notebook for the day, come back the next day, open the notebook and the code within a Module will be misaligned such that it does not run (see attached image).

I will fix the alignment issue, the code will run, then I will close the notebook come back and the same thing has happened.

Thus, every time I open the notebook I have to realign the code. This only seems to happen to code within a Module.

I am not an expert with Mathematica, but have used it for a few years now. I can’t see what I am doing incorrectly as the code runs perfectly (repeatedly) once the notebook is opened and the alignment issue fixed. I can work on the code and it continue to work. The error then reappears when closing and reopening the notebook.

I read that 12.1.1 had some front end issues. Indeed, I was having some of these as well e.g. code randomly formatting as a Wolfram Alpha query.

I am running the latest version, freshly reinstalled today.

Am I missing something obvious?

*** EDITS ***

Sorry about the spelling, despite being 41 I have difficulties in that area which I cannot overcome.

I avoided posting code as the whole notebook is very complex. Here is the module code:

(* Module for plotting for the PSE *)
minXpse = 51.9;
maxXpse = 58.1;
theRangePSE = maxXpse - minXpse;
plotPseData[predPSE0_, combPSE0_, xPSE0_, polyPSE0_, polyDelta0_, 
   visionPSE0_, hapticPSE0_, rsqPSE0_] := Module[
   {predPSE = predPSE0, combPSE = combPSE0, xPSE = xPSE0, 
    polyPSE = polyPSE0, polyDelta = polyDelta0, 
    visionPSE = visionPSE0, hapticPSE = hapticPSE0, 
    rsqPSE = rsqPSE0},
   
   (* Plot the data *)
   
   dataPlot = 
    ListPlot[Transpose[{predPSE, combPSE}], AspectRatio -> 1, 
     Frame -> True, 
     FrameLabel -> {"Predicted PSE" <> xLabelTag, 
       "Observed PSE" <> yLabelTag}, 
     FrameStyle -> Directive[Black, 19, Thickness[0.002]], 
     ImageSize -> Large, BaseStyle -> {FontSize -> 22}, 
     PlotRange -> {{minXpse, maxXpse}, {minXpse, maxXpse}}, 
     Method -> {"AxesInFront" -> False}, 
     PlotLabel -> Style[theTitle, Black, 24], PlotStyle -> Blue, 
     PlotMarkers -> {Automatic, Scaled[0.02]}];
   
   (* Plot the fit *)
   
   fitPlot = 
    ListLinePlot[Transpose[{xPSE, polyPSE}], PlotStyle -> Blue];
   
   (* Plot the error bounds *)
   
   boundsPlot = 
    ListLinePlot[{Transpose[{xPSE, polyPSE + polyDelta}], 
      Transpose[{xPSE, polyPSE - polyDelta}]}, 
     PlotStyle -> {{Blue, Dashed}, {Blue, Dashed}}, 
     Filling -> {1 -> {2}}];
   
   (* Plot the PSE lines *)
   
   visionPSEline = 
    Graphics[{Dashed, Thick, Green, 
      Line[{{visionPSE, minXpse}, {visionPSE, maxXpse}}]}];
   hapticPSEline = 
    Graphics[{Dashed, Thick, Red, 
      Line[{{hapticPSE, minXpse}, {hapticPSE, maxXpse}}]}];
   
   (* Plot the unity line *)
   
   unityLine = 
    Graphics[{Thick, Gray, 
      Line[{{minXpse, minXpse}, {maxXpse, maxXpse}}]}];
   
   (* Report the R^2 *)
   
   rsqText = 
    Graphics[
     Text[Style[
       ToString[Superscript["R", "2"], FormatType -> StandardForm] <> 
        " = " <> ToString[Part[rsqPSE, 1]], 
       18], {minXpse + theRangePSE/2, 57.5}, {0, 0}]];
   
   (* Show *)
   
   Show[dataPlot, unityLine, visionPSEline, hapticPSEline, dataPlot, 
    fitPlot, boundsPlot, rsqText]
   
   ];

It’s not feasible to post the whole code without a bunch of work. The code reads in a bunch of data files (100’s).