Grafana session cookie is deleted/expired only after browser close

I am trying to invalidate a grafana session after 30 secs.
Here is the grafana.ini

[session]
provider = file
provider_config = sessions
cookie_name = grafana_sess
cookie_secure = false
session_life_time = 30

[security]
login_remember_days = 1
cookie_username = grafana_user
cookie_remember_name = grafana_remember

There are only these two sections in the grafana.ini
I am mounting this file into a container as follows -

docker run -d \
-p 3000:3000 \
--name=grafana-kc \
-v conf/grafana-ini:/etc/grafana \
grafana/grafana:5.2.4

Every time the grafana_sess cookie is marked as session which will expire only if I close the browser.
In chrome the expiration date is set to 1969-12-31 which will expire only after the browser close.

I looked at some of the issues, which say the issue is fixed but doesn’t solve the problem
https://groups.io/g/grafana/topic/717530

Is this a issue with 5.2.^. I haven’t tried it with earlier versions. i have tried with 5.2.3, 5.2.4