Reproduction steps:
1. Open the attached “BugRepro” project
2. Open the “Assets/SampleScene“ Scene
3. In the Hierarchy window, select “OriginalText” (Canvas > OriginalText) GameObject
4. In the Inspector window, open the context menu of “Localize String Event” Component’s “Local variables” variable and select “Copy”
5. In the Hierarchy window, select “CopyText” (Canvas > CopyText) GameObject
6. In the Inspector window, open the context menu of “Localize String Event” Component’s “Local variables” variable and select “Paste”
7. Observe the pasted variables

Expected result: The pasted variables' “string” value is the same as in the “OriginalText” GameObject
Actual result: The “string“ value is empty

Reproducible with: 1.3.2 (2021.3.34f1, 2022.3.4f1), 1.4.5 (2021.3.34f1, 2022.3.19f1, 2023.2.8f1, 2023.3.0a16), 1.5.0-pre.5 (2021.3.34f1, 2022.3.19f1, 2023.2.8f1, 2023.3.0b5)

Reproducible on: Windows 11, macOS 14.1.1 (M2 Max) (by user)
Not reproducible on: No other environment tested