Instagram announced via a notification banner within the app that “We hear from our community that they want to see fewer posts in Stories. During this test, you won’t be able to add a feed post to your Story”, said the statement released. However it does not specifically mentions in which countries the feature is being tested in.
The feature used to help promote their posts and have a better reach with the help of the algorithm’s. It is sure that many of the users will not be happy with the new changes but new updates are expected to roll out in the next few months.
Until then users outside of the test community can share post in their stories on Instagram.