I have a simple login flow to show a message before users enter, with a checkbox to "not show this message again" which updates a User field so next login the flow doesn't run past this decision.
The problem is it doesn't work with "Render Flow in Lightning Runtime" checked in the Login flows setup when running in the Salesforce App, but if I deselect it, it works.
I thought the user didn't have enough permissions but the flow works in Lightning if I login from Safari in my phone and from Chrome in my desktop PC, so I don't think it's a permissions issue. Plus, after trying several times I'm able to login with the flow rendering in lightning but only works once and after that, it's back again.
What I see is just the page waiting to load the flow but I've waited up to 10 minutes and nothing changes, so I click "Log out" and try again.
I've noticed one more thing: After downloading the User Login History, I saw that most of them have "success" in the Status column, the ones that did show the flow had "Remote Access 2.0" in the Login Type column, "Salesforce for iOS" in the Application column and "test.salesforce.com" in the Login URL; while the ones that didn't show the flow had "Remote Access Client", "Browser" and my custom domain address respectively.
I tried logging in in the "Sandbox" server in the app thinking it will go to test.salesforce.com like the successful login attempts, but it says that the credentials are invalid.