After making changes and testing your report, make sure to clear any slicer values before publishing, if you have row-level security on a field shown in a slicer and you leave values selected. The selected values will be shown to users when they view the report. For example, let’s say you have created a row-level security role that can only see Product A, but you can see everything, and you left Product A and Product B selected and deployed the report. A user who views the report next and is a member of that RLS role will see the two selected values in the slicer, even though they can’t see the data for Product B on the page. This may not be a big deal for an internal report. But now imagine this is for clients. You don’t want clients to see other clients in the list. This behavior is consistent in the Power BI web service and isn’t specific to embedding. It’s just important to remember this.
There are plenty of interesting notes here, so check it out if you’re thinking of a Power BI project.