Page blanks out when zooming a PDF

When zooming in to make reading a PDF easier, the top 3/4 of the reading pane is blanked out in white.

If I select ‘automatically resize’ the entire pane is blanked out.

On mac the workaround is to use command and +

PDFs have no resize button as regular documents do.

I think you may have encountered a known issue, discussed in more detail here: … rectangles

The workaround is to use Page Breaks view for PDFs, rather than Continuous view.