[blkduc1]

Sounds like what mine does, when it does it, is very similar.

ANd you can feel it start to idle rough, like one cylinder starts to miss, or it gets weak or something. Could the action of the two spark plugs per cylinder working together somehow be affecting the smoothness of idle?

Sure would like to find the solution. ... Could it actually be the fuel pump, as that previous post suggests?

Keep us posted, Peter f.
Perhaps someone here could run the same graphs you did on a flawless bike? Would that be comparable?
dp