Changes not being seen

We are testing an app and the changes that I am making can’t be seen by someone else who is testing the interface. Do I need to publish changes everything for them to see them? Sometimes, depending on the browser that they use they can or can’t see the changes. What could be causing this?

Just to confirm; you have to publish every update that you want people to access

Yes. But even when I do this, changes are sometimes not shown.

Does this happen when you publish content available for everyone, or specific user groups?

Just the general publish, but you need to be logged in to see it