Reproduction steps:
1. Open the project in "BIR.zip"
2. In Scene, zoom out until you can see the entire Shadow of the Cylinder
3. Try adjusting Scene window size or adjusting Scene Camera Near Clipping Planes or Shadow Distance in Quality Settings (check note 3)

Expected result: entire Shadow will not unexpectedly disappear when adjusting these parameters
Actual result: Shadow unexpectedly disappears

Reproducible with: 2019.2. 21f1, 2019.3.4f1, 2020.1.0b1, 2020.2.0a2
Could not test with: 2017.4.37f1, 2018.4.19f1 because I was not able to adjust Camera Clipping Planes in the Scene

Notes:
1. Shadow distance can be changed in Edit -> Project Settings -> Quality -> Shadow Distance
2. Also reproducible with URP, note that the Shadow Distance has to be changed using the Rendering Pipeline Asset and not the Project Quality Settings
3. I noticed that this reproduces when the Shadow is already close to fading due to reaching maximum Shadow distance