Animated Skinned Mesh Renderer.Enable

This is my first question on the Unity forum.

I've imported a model containing animation, which I want to have appear at a certain frame then disappear. So, I've added the property Skinned Mesh Renderer.Enable in the Animation window and added keys to enable the renderer, then disable it.

The animation displays correctly when previewed from the animation window. However in-game the model never appears.

Through experimentation I've found that once the skinned mesh renderer is disabled, it does not reappear. This possibly means the animation stops when disabled. However checking "Update while Offscreen" does not solve the problem.

When adding a script that animates the property, everything works fine. However this is a workaround and it bugs me that it is not possible to simply keyframe it, because to me that is the proper solution.

Is this a problem in Unity or have I missed something? Thank you in advance for your advice.