public int renderQueue { get; }

Since different Render Pipelines require different render passes a shader's render queue depends on the active Render Pipeline. Note: When Unity runs in batch mode, it does not load Scriptable Render Pipelines (SRPs) until the first time something renders. Loading an SRP modifies the sub-shader selected for a given material which can lead to the value this function returns being different than expected.

Additional Resources: Material.renderQueue, RenderQueue enum, subshader tags.