Sub bump stops effect on other channels - intended behavior, or bug?

This is something I noticed the other day while playing around with effects in subs.

If I have some channels playing an effect from a sub, then manually start the same effect on different channels, hitting the bump button on the sub to stop it also stops that effect on the manual channels.  Reversing the order of methods to start the effect (manually play an effect on some channels, then start the same effect on different channels from a sub, then stop the sub with the bump button) does not cause the manual channels to stop.

Is this intended?  I would think starting and stopping a sub should only affect channels in the sub and nothing else.

Matthew Rohn
IATSE Local 52

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