What SP were they facing? I though that the moment you dual weapons during SP dropping it stops working.

This hangar does have me questioning what I knew about SP dropping so far :-).

It was pitted against a 1250 SP hangar of mine, five 2-3 star mechs, all common and uncommon except for Guardian (also at 3 stars). Some of the mechs had 3-star legendary weapons on them (viper 6s and gemini 8s, obtained through recent events). All weapons were at 3 stars.

In case you're interested, here are the mvps from that match:

i

Saw this kind of thing again on another player today. It used to happen in the past to some extent when I first started playing. Then I hadn't seen it for a long time. Now it seems to have picked up again. 

I don't know if that is because of changes in matchmaking rules (for the worse), or because people are rediscovering old ways of SP dropping.. or maybe I've just been fortunate not to encounter these until now.

Matchmaking seems to have "improved" somewhat. Players I face are no longer 6000+ SP compared to my 4.3K SP hanger.

It seems that whenever MM improves for higher level players, SP dropping also worsens.