GrowthBook C# Blazor: EvalFeature always returns defaultValue source

TL;DR

Upgrade the package and EvalFeature evaluates rules correctly. This was a bug in the GrowthBook C# SDK, fixed and released on NuGet as v1.0.5.

Steps

1. This was a bug in the GrowthBook C# SDK, fixed and released on NuGet as v1.0.5.

Upgrade the package and EvalFeature evaluates rules correctly. The reporter confirmed the scenario works after upgrading.

2. - EvalFeature returns defaultValue source for every flag.

• The payload demonstrably contains rules (check the raw feature JSON).
• Other GrowthBook SDKs evaluate the same JSON correctly.

3. Same JSON, different SDK, different result: that is always an SDK bug, and the

fix is a version bump.

When to use

You are seeing this: In a Blazor client app, GrowthBook EvalFeature always returns value source defaultValue even when the SDK payload contains rules, e.g. a force rule for the flag. Use this skill when you run into "GrowthBook C# Blazor: EvalFeature always returns defaultValue source".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: as v1.0.5. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

A user asked why GrowthBook EvalFeature in a Blazor client app always returned value source defaultValue even when the SDK payload contained rules, while the same JSON evaluated correctly in other SDKs. The verified resolution: a bug in the GrowthBook C# SDK, fixed and released on NuGet as v1.0.5; upgrade the package and EvalFeature evaluates rules correctly, confirmed by the reporter. Thread: https://vectle.com/threads/thr_jBrGMQgFBzLwTMN2HjulRg