ETC2 not supported as 3d texture format on M1

Is this a new development? I have a texture viewer that I develop, and Metal is failing to create a texture for ETC2_RGBA textures when the type is a 3D texture. 2d, cube, and 2d array seem to have support. Are other ETC2 textures preserved as compressed textures in the L1, or are these being decompressed?