Unable to track gained or lost User Permission in Profile
|Knowledge Article Number||000188095|
If you're unable to track a gained or lost User Permission to a profile using Setup Audit Trail, this would indicate that the modification to the profile was done by a Change Set.
Validate modification by Change Set
The ability to change a User Permission using Change Sets has been standard functionality since Winter '14, here's how you can validate the source of a change.
NOTE: Changes to User Permissions made via Change Sets don't get tracked in the Setup Audit Trail. If this is functionality you'd like to see added, vote for the idea on IdeaExchange.