I don't think they are losing on purpose.
However, I do believe they are holding back "stuff" that they are working on in practice (new plays, exp "stuff" for Jeff Green) and they are holding back on effort. In addition, I also think Doc is experimenting with different rotations.
Rondo has been holding back, letting the shot clock wind down on almost every possession. Then, you have to wonder, does Doc tell them to play hard for a few, Rondo pushes it and you get a 12-0 run? I'm not sure but if Bibby doesn't hit that lucky 3 from the corner, maybe they close to 8 and who knows?
Whatever is going on, only the guys in that locker room know for sure but it's peculiar to say the least.