Steps to reproduce:
1. Create a new 3D project
2. In the Toolbar select Window > UI Toolkit > UI Builder
3. In the Library pane of the UI Builder window, under Controls, drag the Scroller element into the Hierarchy pane
4. In the Hierarchy pane expand the initiated Scroller element and then select the "#unity-slider" element
5. In the Inspector pane, under the Slider section observe that the parameter "Inverted" is unchecked
6. In the Viewport pane click File > Save
7. In the Inspector pane, under the Slider section observe the parameter "Inverted"

Expected result: the parameter "Inverted" remains unchecked
Actual result: the parameter "Inverted" becomes checked

Reproducible with: 1.0.0-preview.18 (2019.4.37f1, 2020.3.31f1), built-in UI Builder (2021.2.16f1, 2022.1.0b13, 2022.2.0a8)

Notes:
- Reproducing this issue in 2019.4.37f1 and 2020.3.31f1 requires "UI Builder 1.0.0-preview.18" and "UI Toolkit 1.0.0-preview.18" packages to be installed
- In 2019.4.37f1 and 2020.3.31f1, the "#unity-slider" element doesn't have the parameter "Inverted", however, in 2020.3.31f1 this inversion can be observed by clicking Preview in the Viewport pane and then clicking the arrow-ends of the Slider. In 2019.4.37f1 the Slider doesn't function in the Preview at all after performing step 6