Clear Interval not working in my component JavaScript? - reactjs

Question

I have a component that will start counting down from 5 mins when a timestamp (obsTakenTime) is received via props. When the countdown gets <=0, I render ‘Overdue’. At this point I need to clear interval which I think I've done, the issues is when if, I refresh the page the obstimeleft should remain overdue but the countdown automatically starts from 59 mins because the value of nextObservationTime becomes 59min and this.state.obsTimeleft becomes undefined even thought the value of timestamp obsTakenTime is the same. I've looked at other similar threads on SO but I couldn't get mine to work. Any help is appreciated.
similar post - Clear interval in React class
Countdown component
export default class ObservationCountDown extends React.Component {
constructor(props) {
super(props);
this.state = {
obsTimeleft: undefined
};
this.countDown = this.countDown.bind(this);
this.startCounter = this.startCounter.bind(this);
this.countDownInterval = null;
}
countDown() {
const { obsTakenTime} = this.props; //when last obs was taken by the user in ms
const nextDueTimeForObs = moment(obsTakenTime).add(5, 'minutes');
const nextObservationTime = Number(nextDueTimeForObs.subtract(moment.now()).format('m'));
const timeToDisable = 2; // disable buttons time
this.setState({ obsTimeleft: nextObservationTime + ' min' }, () => {
if (nextObservationTime <= Number(timeToDisable)) {
this.props.disablePatientUpdate();
}
if (nextObservationTime <= 0) {
clearInterval(this.countDownInterval); // doesn't work here
this.setState({ obsTimeleft: 'Overdue' }, () => {
if(this.state.obsTimeleft === 'Overdue'){
clearInterval(this.countDownInterval); // doesn't work here
}
});
}
});
}
componentDidMount() {
this.startCounter();
}
startCounter() {
this.countDownInterval = setInterval(this.countDown, 1000);
}
componentDidUpdate(prevProps){
if(this.props.patient.timestamp !== prevProps.patient.timestamp){
this.startCountdown();
}
}
componentWillUnmount(){
clearInterval(this.countDownInterval);
}
render() {
const { obsTimeleft } = this.state;
return (
<>
{(obsTimeleft && obsTimeleft === 'Overdue') ?
<div className="text-danger">
<strong>{obsTimeleft}</strong>
</div> :
<div>
<strong>{.obsTimeleft}</strong>
</div>}
</>
);
}
}
another version of countDown() that I tried and didn't work
countDown() {
const { obsTakenTime } = this.props; // obs duration - when last obs was taken by the user in min
const nextDueTimeForObs = moment(obsTakenTime).add(2, 'minutes');
const nextObservationTime = Number(nextDueTimeForObs.subtract(moment.now()).format('m'));
console.log('nextObservationTime', nextObservationTime);
this.setState({ obsTimeleft: nextObservationTime + ' min' })
if (nextObservationTime <= 0) {
this.setState({ obsTimeleft: 'Overdue' }, () => {
if(this.state.obsTimeleft === 'Overdue') {
clearInterval(this.countDownInterval);
}
});
this.props.enablePatientUpdate();
this.props.resetPatient(patient);
}
}