React Material UI - Why CSS classes are getting repeated, when using withStyles?

CSS classes are getting repeated while execution, any particular reason for this?

<Grid
      item
      xs={12}
      md={12}
      className={classes.subFilterWrapper}
      data-locator={locators.COMPONENT_SUBFILTERWRAPPER}
    >
    </Grid>

Above code resulting into

<div class="MuiGrid-root MuiGrid-root makeStyles-subFilterWrapper-4108 MuiGrid-item MuiGrid-item MuiGrid-grid-xs-12 MuiGrid-grid-xs-12 MuiGrid-grid-md-12 MuiGrid-grid-md-12" data-locator="ProductCardList-SubFilterWrapper"></div>