Hi Brian,
No, it's not trunk, I updated ~2 weeks ago.

Is this a known issue and updating to trunk will fix this problem?

I tried Anthony's suggestion with waiting for park AND answer events to
begin call processing... and I pasted another scenario. Call are bridged
correcly and can talk to each other, but hanging up 2nd call ends up in
hanging up the first one with ORIGINATOR_CANCEL cause...
Here it is, < 290 lines of commented logs:
http://pastebin.freeswitch.org/12468