Diego’s neighbors have been disturbing his sleep. (This implies that it has been happening recently and with some regularity, but it could have started at any time, and since it is not happening at this precise moment, it could conceivably have already stopped, which would come as a surprise.) They have disturbed Mary’s sleep occasionally too, but that was only on nights when Mary visited Diego.

The first time they disturbed Diego’s sleep was actually over a year ago. They disturbed Mary‘s sleep the first time she visited Diego, but not the second. Sadly, it seems Diego’s neighbors often disturb their sleep, but it won’t happen tonight, because Diego and Mary have other plans.

Since it expresses continuity, it can be expressed in the present perfect or the perfect progressive. It is more common to express it in the perfect progressive than in the present perfect.