How to reproduce:
1. Open the attached “case IN-7005” project
2. Open the “Test” Scene
3. Select the “User” GameObject in the Hierarchy
4. Open the Object Selector for the “Target 2” field in the Inspector

Expected result: “Target 2” GameObject is suggested to select
Actual result: No suggestions are presented

Reproducible with: 2020.3.37f1, 2021.3.7f1, 2022.1.11f1, 2022.2.0b3, 2023.1.0a4

*Workaround*:
Remove the namespace specifier in the search query (i.e., change "t:searchtest.searchtarget2" to "t:searchtarget2")