Shallow component not updating on jest.fn call - node.js

Question

After updating a series of dependencies, most notably jest and react/react-dom, a once working Unit Test is no longer working. After spending the last week reading through the ChangeLogs of the dependencies that changed, I still cannot find out why it is breaking.
The Component - stripped down for the relevant portions
[imports, etc.] ->not code, just giving a stripped down version
class MyComponent extends React.Component {
render() {
const { Foo, errorNotice, disabled } = this.props;
return (
<form autoComplete="Off">
<Paper className="top-paper edit-form">
<h1>{ Foo.id ? 'Edit' : 'Add' } My Foo </h1>
<div className="flex">
<div className="flex-column">
<FormControl
className="has-columns"
component="fieldset"
>
<TextField
id="foo-name"
fullWidth={true}
disabled={disabled}
name="name"
inputProps={{ maxLength: 50 }}
className="block"
label="Name"
value={Foo.name}
onChange={this.props.onChange}
error={!!errorText.name}
helperText={errorText.name}
/>
[closing tags, etc.] -> as as above, not code, just giving a stripped down version
export default MyComponent
The Test
import React from 'react';
import { shallow } from 'enzyme';
import MyComponent from "./my-component";
const Foo = {
name: 'Foo Name',
val_x: 'NONE'
};
const handleTextChange = jest.fn(({ target: { name, value} }) => {
Foo[name] = value;
testMyComponent.setProps({ Foo });
});
const testMyComponent = shallow(
<MyComponent
Foo={Foo}
errorNotice={{}}
onChange={handleTextChange}
/>
);
describe('Test component display', () => {
it('Name field show display attachment point name', () => {
const nameInput = testMyComponent.find('[name="name"]');
expect(nameInput.props().value).toBe(Foo.name);
});
});
^^ This Test Passes
describe('Test Foo interactions', () => {
it('Updating Name field should update Foo name', () => {
const newName= 'New Name';
testMyComponent.find('[name="name"]').simulate('change', {
target: { name: "name", value: newName }
});
expect(testMyComponent.find('[name="name"]').props().value).toBe(newName);
});
});
^^ This Test Fails on the 'expect' line. The name remains the old name, 'Foo Name'
The output when I call testMyComponent.debug() after the .simulate('change' is as follows (again stripped down)
<WithStyles(ForwardRef(TextField)) id="foo-name" fullWidth={true} disabled={[undefined]} name="name" inputProps={{...}} className="block" label="Name" value="Foo Name" onChange={[Function: mockConstructor] { _isMockFunction: true, ... , results: [ Object [Object: null prototype] {type: 'return', value: undefined } ], lastCall: [ { target: { name: 'name', value: 'New Name' ....
^^ So I can see through lastCall that the handleTextChange function is being called, but its not actually performing the update. Moreover, if I put a test for
expect(handleTextChange).toHaveBeenCalledTimes(1);
Then that text passes, it effectively gets called. But again, the update doesn't actually occur.
The dependencies that were changed were
react 16.13.1 -> 17.0.2
react-dom 16.13.1 -> 17.0.2
jest 24.9.0 -> 27.5.1
material-ui/core 4.11.0 -> 4.12.13
but enzyme stayed the same a 3.11.0
Does any of this make any sense? Like I mentioned I've read changelogs and update posts on all of the dependencies that were updated and I cant see anything that needs to change in the test, but clearly it is failing. I have read Jest/Enzyme Shallow testing RFC - not firing jest.fn() but the solution there is not working for me. I should also mention I have called .update() on the component but to no avail.