We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither. This is good, in that the MCL is doing what it ought to do. However, we need to turn it off before doing a spot measurement.
This is totally non-sensical statement, of course.
We might also say that the DARM loop totally squishes the GW signal and so its better not to have any feedback in the interferometer.