Flow to modify file access for a user runs successfully, but does nothing.

[RobGlprFan]

Hello

I've built a Power App that manages team tasks.  A user is able to create a task and assign other team members as contributors to the task.   The task creator can then upload files and the other team members are able to review and make changes to the files (mostly MS Word, and MS Excel files).  Once a contributor is done with their edits, they can indicate this in the Power App, and they lose edit permission to the file.  

File management is handled by SharePoint in a document library.  My issue is, I'm having trouble getting file permissions to update from "edit" to "view" in SharePoint.  

Just for reference, I have two flows.  The first runs when the task creator uploads a file.  This first flow breaks inheritance and assigns all contributors "edit" access to the file.  The second flow runs when a contributor indicates they are done making edits.  This second flow is supposed change the user's permission from "edit" to "view", however, even though the flow executes successfully, the file permissions do not change.  What's even stranger is if I reverse the permission process (i.e., I have the first flow grant "view" access" and the second flow grant "edit" access), everything works fine!!  So for some reason, by second flow can change permissions from view to edit, but the not the other way around?? 

I am utilizing a HTTP request to update the permission (I also tried using the SharePoint "Grant access to an item or folder" action but got the same results).  Here's the flow:

Anyone run into this issue before?  Is there a workaround?  

[RobGlprFan · Accepted solution]

I solved this issue by first deleting the user's permissions via an HTTP request to SharePoint with the DELETE method, then granting the user access.