Thousand separator issue in fr-FR culture in .Net 8 on Windows 2022

[GTechene]

Description

When running a simple test involving the thousand separator in fr-FR culture in .Net 8 on Windows 2022 build agent, it fails. The same test performed locally (Windows 11) or on an Ubuntu build agent works fine. I haven't tested on other versions of Windows.

The test fails because the thousand separator for French numbers in .Net is supposed to be the U+202F character (narrow no-break space) but on Windows 2022 build agent this character is inexplicably replaced with a regular space (i.e. U+0020). If you copy/paste the logs you get :

Expected: "1 000 €"
But was:  "1 000 €"

The space beween "1" and "0" on the Expected line is actually U+202F while the other one is U+0020. Hence the failing test.

Is it some kind of config issue for the .Net Framework that is installed on the image ? Or the culture specs in the OS (e.g. regional settings in registry) ?

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 20.04
• Ubuntu 22.04
• Ubuntu 24.04
• macOS 12
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

Version: 20250120.2.0

Failed build : https://github.com/GTechene/VerifyThousandSeparator/actions/runs/12966472782/job/36167269110
Reproducible at will with this image version.

Is it regression?

Possibly, I do not know.

Expected behavior

The following .Net test should pass on all build agents :

using NUnit.Framework;

namespace VerifyThousandSeparator;

public class TestClass
{
    [Test]
    [SetCulture("fr-FR")]
    public void Should_not_fail_with_basic_assert()
    {
        const decimal input = 1000.31m;
        Assert.That($"{input:C0}", Is.EqualTo("1\u202f000 €"));
    }
}

Please find a complete project at https://github.com/GTechene/VerifyThousandSeparator

Actual behavior

The test fails only on Windows 2022 build agent, not locally (Windows 11) or Ubuntu 24.04 build agent.

Please find a complete project at https://github.com/GTechene/VerifyThousandSeparator

Repro steps

Run the windows workflow that can be found at https://github.com/GTechene/VerifyThousandSeparator/actions

[RaviAkshintala]

Hi @GTechene Thank you for bringing this issue to our attention. We will look into this issue and will update you after investigating.