Resource based localization not working for flags enum

Describe the bug

I’m using localization in my ASP .Net Core WebApplication (.net 5). Translation of a (flags) enums work perfectly, but when I have a value with more than one flag it does not translate, as seen in the screenshots below:

en-US: nl-NL:

Translation of a single item (Missing) works, translation of a value with 2 flags (LampFailure and Missing) doesn’t work.

To Reproduce

Included is a solution (WebApplication1.zip). In this solution identity is also added to be able to quickly change the UI language, to change it:

• Create a user account
• Login
• Go to the user profile page and change the Language with the pull down menu.
• Go back to the home page to see the test values.

Exceptions (if any)

Further technical details

• ASP.NET Core version: 5
• Include the output of dotnet --info:

.NET SDK (reflecting any global.json):
 Version:   5.0.201
 Commit:    a09bd5c86c

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19042
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.201\

Host (useful for support):
  Version: 5.0.4
  Commit:  f27d337295

.NET SDKs installed:
  3.1.407 [C:\Program Files\dotnet\sdk]
  5.0.201 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE:

Microsoft Visual Studio Community 2019 - Version 16.9.2
VisualStudio.16.Release/16.9.2+31112.23

[whvanderpost]

Thanks for contacting us. Please provide the repro app as a minimalistic GitHub repo. We won’t b e able to use repros in other formats going forward.

repro available: https://github.com/whvanderpost/core-issue-repro

[hishamco]

Looks good