I have a short drop-down slicer on one of my report pages that has 3 items. On desktop, when I click the drop-down I see all options upon first click, just like so:
However, when I publish the report, all users, myself included, only see a single item in the drop-down when the slicer is clicked the first time (see pic below). When a user clicks on the slicer the second time (and any time thereafter), they see the "full" dropdown and all three items like it appears on desktop.
This is confusing to users as its not obvious that there are additional options and the scroll bar only appears if you hover over the scroll area. This is a single-select slicer that is on the topmost layer of the report page and isn't being covered by any other item.
This behavior can be seen in every report slicer that has a "small" amount of items (generally <5) -- a user must click the drowpdown, exit, then re-click the slicer dropdown in order to see all the items when viewing the report in the web browser. Again, every user, regardless of access level or web browser, sees this same behavior. And its on every report that has slicer with a small amount of items, its not limited to this single report example.
If it helps any, I'm on the Power BI Premium service and the desktop version I'm using is Version: 2.92.1067.0 64-bit (April 2021)