How to reproduce it:
1. Open Windows Display Settings and set the UI Scaling to 150%
2. Open the user's attached project "URP Testing.zip"
3. Double-click on "NewUXMLTemplate.uxml" file to open a UI Builder view
4. Replace an existing VisualElement with a new one
5. In the UI Builder's Viewport resize the VisualElement by dragging its corner
6. In the UI Builder's Inspector view observe the VisualElement's size fields

Expected result: The values remain small and don't jump to very high numbers
Actual result: The values suddenly become very high

Reproducible with: 1.0.0-preview.8 (2020.3.2f1), 1.0.0-preview.14 (2021.1.0f1), Built-in UI Toolkit (2021.1.0f1, 2021.2.0a10)
Not reproducible with: 1.0.0-preview.7 (2020.3.2f1)
Could not test with: 2018.4.33f1, 2019.4.23f1 (UI Toolkit is not introduced yet)

Notes:
- Not reproducible the first time, need to repeat 5 and 6 steps few times
- Not reproducible when UI Scaling is 100%
- Only reproducible, when VisualElement's size values are in 'px'
- In 2020.3.2f1 used an UI Builder (1.0.0-preview.13), and in 2021.1.0f1, 2021.2.0a10 versions used Built-in UI Builder and UI Builder package (1.0.0-preview.13)