Here it is:
This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
Suddenly the lines aren't appearing on shapes in the stencils. For ex., on the Cross-functional stencil, the separators have no lines showing at all.
And 1/2 pt outlines on shapes in the doc don't appear if I zoom out to less than 100%. 3/4 pt lines appear at 75% zoom but not less than that. 1 pt lines at 67% but not less than that.
This wan't happening 2 days ago, the last time I used Visio.
I was always able to see the outline around the shapes no matter how far out I zoomed. Also note that you can't tell that one of these shapes is a predefined process without being able to see the lines.