I have successfully resolved the Column issue, and I believe this solution will benefit you as well. Please review the updated file below:

demo.js

    import React from "react";
    import Table from "@mui/material/Table";
    import TableBody from "@mui/material/TableBody";
    import TableCell from "@mui/material/TableCell";
    import TableContainer from "@mui/material/TableContainer";
    import TableHead from "@mui/material/TableHead";
    import TableRow from "@mui/material/TableRow";
    import Paper from "@mui/material/Paper";
    import { Box, Button } from "@mui/material";
    import AddIcon from "@mui/icons-material/Add";
    import { FieldArray, Form, Formik } from "formik";
    import CustomTableRow from "./CustomTableRow";
    
    const CustomTable = () => {
      const handleSubmit = () => {};
    
      return (
        <TableContainer component={Paper}>
          <Formik
            initialValues={[
              {
                id: 1,
                attribute: "",
                ruleId: "",
                thirdRow: ""
              }
            ]}
            onSubmit={handleSubmit}
          >
            {({ values }) => (
              <Form>
                <FieldArray
                  name="rows"
                  render={(arrayHelpers) => (
                    <React.Fragment>
                      <Box>
                        <Button
                          variant="contained"
                          type="submit"
                          startIcon={<AddIcon />}
                          onClick={() =>
                            arrayHelpers.unshift({
                              id: Date.now(),
                              attribute: "",
                              ruleId: "",
                              thirdRow: ""
                            })
                          }
                        >
                          Add New
                        </Button>
                      </Box>
                      <Table sx={{ minWidth: 650 }} aria-label="simple table">
                        <TableHead>
                          <TableRow
                            sx={{
                              th: { border: 0 }
                            }}
                          >
                            <TableCell>Attribute</TableCell>
                            <TableCell>Rule ID</TableCell>
                            <TableCell colSpan={2}>Actions</TableCell>
                          </TableRow>
                        </TableHead>
                        <TableBody>
                          {values.rows?.map((row, index) => (
                            <CustomTableRow
                              key={row.id}
                              row={row}
                              index={index}
                              arrayHelpers={arrayHelpers}
                            />
                          ))}
                        </TableBody>
                      </Table>
                    </React.Fragment>
                  )}
                />
              </Form>
            )}
          </Formik>
        </TableContainer>
      );
    };
    
    export default CustomTable;

CustomTableRow.js

    import { TableCell, TableRow, TextField, IconButton } from "@mui/material";
    import { FastField } from "formik";
    import RemoveCircleOutlineIcon from "@mui/icons-material/RemoveCircleOutline";
    import { Button } from "@mui/material";
    const CustomTableRow = ({ row, index, arrayHelpers }) => {
      return (
        <>
          <TableRow
            sx={{
              "th, td": { border: 0 }
            }}
          >
            <TableCell component="th" scope="row">
              <FastField
                name={`rows.${index}.attribute`}
                component={TextField}
                fullWidth
              />
            </TableCell>
            <TableCell>
              <FastField
                name={`rows.${index}.ruleId`}
                component={TextField}
                fullWidth
              />
            </TableCell>
            <TableCell>
              <FastField
                name={`rows.${index}.ruleId`}
                component={TextField}
                fullWidth
              />
            </TableCell>
          </TableRow>
        </>
      );
    };
    
    CustomTableRow.displayName = "CustomTableRow";
    
    export default CustomTableRow;

Double-check your imports to ensure all necessary Material UI components are loaded, especially the Grid component for organizing columns.

Review your code to confirm that the Props and Syntax for the Grid component are correct, ensuring that the xs, sm, md, lg, and xl props add up to 12 as the Grid component follows a 12-column layout.

import { Grid } from '@material-ui/core';
    
    function App() {
      return (
        <Grid container spacing={2}>
          <Grid item xs={12} md={6}>
            {/* Content for left column */}
          </Grid>
          <Grid item xs={12} md={6}>
            {/* Content for right column */}
          </Grid>
        </Grid>
      );
    }

Avoid any CSS styles that may clash with Material UI designs by checking for conflicts. Also, be mindful of the total cost-effective date when working on your project.