In the December 2021 release, the scroll bar is missing from the Sync Slicers pane. This means that if you have more pages than can fit in one pane you cannot scroll to the rest of the pages or reach...
It appears that if the model was built with an earlier version of Power BI (pre Dec 2021?) and there were enough Slicers present to force the Scroll Bar to appear, then the current version (Feb 2022) of Power BI recognises the existence of the scroll bar. The Sync Slicers pane works Ok, you can access the "Advanced options" button and it does not appear as if there is a problem.
Once you create a new Workbook, the problem reappears. Once you have more than a certain number of Slicers, you cannot scroll down, cannot see the slicers in newly added pages nor can you access the "Advanced options" button.