I don't have all those plugins so I can't open it. I made a test and everything seems to be working fine with the paster object from my end.
I added a sprite and a paster object to the layout. Then made an event:
start of layout:
--- paster: clear to (0,0,0,100)
--- paster: paste sprite
--- browser: invoke download of paster.imageUrl
That worked fine. Even when changing the sprite's blend mode to any of the others. The only exception is xor, which doesn't work with webgl, but that is C2 wide.