styles work on the front end but not in the editor while extending a core block

I’m trying to add box shadow to the core group block.
I’m using filters, since we are talking about extending a core block and not creating a block from scratch.
The issue is that all works correctly in the front end but I cannot make the changes display in the editor itself.

This is my getSaveContent filter function:

const ApplyBoxShadow = (extraProps, blockType, attributes) => {
    const {
        horizontalAxis,
        verticalAxis,
        blurAmount,
        spreadAmount,
        shadowColor,
        inset
    } = attributes;

    //console.log('the extra props: ', blockType.name);
    if (blockType.name == 'core/group') {
        Object.assign( extraProps, { style: { 'box-shadow': `${horizontalAxis}px ${verticalAxis}px ${blurAmount}px ${spreadAmount}px ${shadowColor}` } } );
    }

    return extraProps;
}

wp.hooks.addFilter(
    'blocks.getSaveContent.extraProps',
    'gutrs/gutrs-box-shadow-style',
    ApplyBoxShadow
);

Any idea why this is working in the front but not in the editor?

best regards