String.CompareOrdinal intermittently return non-zero for non-unique instances of empty strings when Mono scripting backend is used

How to reproduce:

1. Open the attached “IN-128137” project

2. Make sure “Windows Mono”/”Mac Mono” profile is selected, in Build Profiles
3. In the Test Runner tab, make sure “Player” option is selected

4. Click “Run All” and wait for the results

5. Observe the Test Runner tab

Actual result: The test fails

Expected result: The test passes

Reproducible with: 2023.1.0a3, 6000.0.66f1, 6000.3.5f1, 6000.4.0b4, 6000.5.0a5

Reproducible on: Windows 11, macOS 26.2 (M1 Pro)
Not reproducible on: No other environments tested

Note: The test does not fail when using IL2CPP