Power BI Service defaults to selecting an element when new report page is loaded (Black rectangle)

[Pentti]

Today noticed that when a new report page is loaded, an element (always the same) is selected by default. This selected element is marked by a black rectangle around the element. Using <tab> let's you cycle through the elements. 
The black rectangle is visually disturbing. Once you click on the report the selection vanishes. 
Tested with reports in different tenants, also verified by another user on a different computer. Both used Chrome browsers.

[nickhukriede]

Just following up on this again, it appears to happen only when I use a page navigation button to change pages in my report. If I manually click on the pages no black border ever appears. Thoughts?