glGetFramebufferAttachmentParameteriv with GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING returns wrong value

Gaming and Visualization Technologies APIs OpenGL
1

The environment spec: Windows 10, GPU NVIDIA Quadro P1000, driver version 27.21.14.5296

I have created an OpenGL application using GLFW library. The default framebuffer supports SRGB:
glfwWindowHint(GLFW_SRGB_CAPABLE, 1);

After calling glEnable(GL_FRAMEBUFFER_SRGB) I get a desired result on the screen when render a test texture.
Unfortunately glGetFramebufferAttachmentParameteriv returns wrong result for the default framebuffer:

GLint encoding = 0;
glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_BACK_LEFT, GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING, &encoding);

The encoding variable equals GL_LINEAR but should be equal to GL_SRGB according to the OpenGL documentation (please see IsDefaultFramebufferLinear example function).