Reflection probes using mode "Custom" allow using an external cube texture as the reflection texture.
Render texture can be of type cube texture.
It is currently impossible to use a Cube Render texture as a custom reflection probe texture.

Expected behavior :
It is possible to use a render texture as a custom reflection probe texture.
If the render texture is animated then the reflection probe texture should be updated in order to reflect the animation.

Repro :
Using the attached project :
- open "SampleScene"
- Select "Reflection probe" in the scene
- try assigning "TestRenderTextureCube" in the reflection probe's "Cubemap" slot
-> currently it won't work