Another interpretation is that the apparatus and not just light is made from ether — and so the signal is lost because the measuring apparatus is also subject to the local distortion.

That interpretation is also consistent with LIGO: we can detect those ether disturbances because the distortion of our motion on the apparatus doesn’t cancel the signal in the same way.

> Another interpretation is that the apparatus ... is made from ether

Or maybe an invisible pink unicorn is sneaking into the lab at night and tweaking things.