Softsynth stops working

[Dave Modisette]

I am a Windows 7 native user

I am running into an intermittent issue where a softsynth in a insert bin stops working. It's sort of like it's been disconnected.

I've check to see if I have inadvertently bypassed it.
I've checked to see if I have disabled it.

The only remedy once the Instrument track is in this state is to delete the softsynth and then place it back into the insert bin.

It's happened with Xpand! as well as Toontrack products.

I'm wondering if it's me hitting an odd key combination that is disabling the soft synth or if this is a known issue. (I did a couple of searches but didn't find a keyword that came up with the issue.)