When you hover over an option in a drop down filter, the tooltip showing the full option no longer appears. It still works fine in Desktop.
I have the same issue, I first noticed this yesterday. Indeed the problem does not occur in Power BI desktop, only in Service. I have checked for Google Chrome and Mozilla Firefox, both have the issue.
To be clear, the tooltip that shows the full item does not appear at all on drop down selection for a slicer. This means that some 'longer' data-items can not fully be shown. Thus it is a big issue for a slicer with long items where the beginning of several values are the same or similar.
It only is a problem with slicers. This 'simple' tooltip still appears normally on items in other visuals like matrices, graphs and cards, when no functional tooltip is assigned.
Please fix this issue, as a lot of our slicers depend on this tooltip.