Reproduction steps:
1. Open the attached “IN-96629.zip” project
2. Open the “SampleScene”
3. From the Hierarchy, select the “TestObject” GameObject
4. Observe the “TestMonobehaviour” Component in the Inspector

Expected result: All the list items are named as "Custom Property Name <index>"
Actual result: All the list items are named as "Element <index>"

Reproducible with: 1.21.15, 1.23.1 (2022.3.59f1), 2.0.3, 2.3.16 (6000.0.41f1, 6000.1.0b10, 6000.2.0a6)

Reproducible on: Windows 11, macOS 15.3.1 (M3 Max)
Not reproducible on: No other environment tested