I wrote this automation to grant Power Apps access to users who request it. I gotta say this connector does save a lot of time granting access for app makers. However, the connector has some issues (not sure if they are bugs or not). I wonder whoever's familiar with this connector can give me some advice here.
Here the parameters for my "Edit App Role Assignment" connector:

Here's the response after the automation runs:

All works fine with no error. However, some of the users can open the app after they are give the access and some can't even though they got the email notification saying that they got the access.
When I open Power Apps permission panel, I see some differences between the users granted by automation and manual settings. The users with access granted by automation look like this. They have no profile photo, no display name:

while users with access granted manually look like this, they have profile photo and display name:

On the other hand, the users with access granted via automation cannot be managed manually in Power Apps permission panel, meaning that I cannot mannually remove them from the user list. I can only remove them via automation using "Edit App Role Assignment" connector.
I wonder if somebody knows what's going on or has solution here. It would be much appreciated.