Unresponsive behaviour with line~ object inside poly~

I'm currently trying to create a poly~ object so that a trigger will cause a given voice to play for a random length of time. To do this, I'm using the line~ object to increase the amplitude upon receiving an initial bang, and then to decrease the amplitude once a clocker has elapsed.

However, when I open the poly~ object I created the line object seems to be unresponsive to a bang or even when I click the 0, 1 50 message. line~ seems to work fine in the Tutorial examples. I'm wondering if it's something to do with the presence of buffer objects and wavefaderms, though I can't imagine why.

Any help is greatly appreciated, thank you.