Deneb Matrix Visual - Working but with Warnings

One of the x2 sections is creating a shaded rectangle in color #004ABF where x describes the beginning x position and x2 describes the ending point to draw the rectangle:

          "mark": {
            "type": "rect",
            "tooltip": true,
            "color": "#004ABF",
            "opacity": 0.5
          },
          "encoding": {
            "x": {
              "field": "MBRPVCTable",
              "type": "nominal",
              "bandPosition": -2 //WARNING: Value is below the minimum of 0.
            },
            "x2": {
              "field": "MBRPVCTable", //WARNING: Property field is not allowed.
              "type": "nominal",
              "bandPosition": 3 //WARNING: Value is above the maximum of 1.

The other x2 sections where I have warnings are creating two different horizontal lines at specific points in the table.  The below code section does the horizontal line that shows above 'Cost' in my sample image and "x" is the starting x position whereas "x2" is the ending position for the line/stroke.

      "transform": [
        {"filter": "datum.MBRPVCTable === 'COR'"}
      ],
      "mark": {
        "type": "rule",
        "tooltip": true,
        "strokeWidth": 1,
        "color": "black"
      },
      "encoding": {
        "x": {
          "field": "MBRPVCTable",
          "type": "nominal",
          "bandPosition": 0
        },
        "x2": {
          "field": "MBRPVCTable", //WARNING: Property field is not allowed.
          "type": "nominal",
          "bandPosition": 5 //WARNING: Value is above the maximum of 1.
        },
        "y": {
          "value": -35  // Position the top horizontal line
        },
        "y2": {
          "value": -35  // Ensure the line is horizontal

The code below here is the 2nd horizontal line that shows at the bottom of the visual in my sample picture.

      "transform": [
        {"filter": "datum.MBRPVCTable === 'Other'"}
      ],
      "mark": {
        "type": "rule",
        "tooltip": true,
        "strokeWidth": 1,
        "color": "black"
      },
      "encoding": {
        "x": {
          "field": "MBRPVCTable",
          "type": "nominal",
          "bandPosition": -4 //WARNING: Value is below the minimum of 0.
        },
        "x2": {
          "field": "MBRPVCTable", //WARNING: Property field is not allowed.
          "type": "nominal",
          "bandPosition": 1
        },
        "y": {
          "value": {"expr": "height"}  // Position the bottom horizontal line
        },
        "y2": {
          "value": {"expr": "height"}  // Ensure the line is horizontal

 I guess the line has the same x for both horizontal lines, I'm just using a different starting point and hence why one has a negative bandPosition of -4 going to 1 whereas the other goes from 0 to 5.  Again, I am brand new to Deneb, so the different starting points for the lines comes from Copilot, but it worked so I didn't analyze and question why to not use the same starting x position 'COR'.