Breverb and Unusual Multi Core Processing Observation

Hi everyone,
 
I have a project, 48 K and 24 bit, that was very heavily using one core on my machine (specs below) on Sonar Platinum build 22.10.0 Build 19 (2016.10) x64 and the most recent one 2016.11.  This was happening with load balancing on and multicore processing on.
 
When all the fx were bypassed, the problem went away, so I turned off effects one by one and isolated it to a buss that had one instance of Breverb.  When this instance of Breverb was toggled off the problem stopped an all cores resumed uniform use.  I took off the instance and added another instance and could not repeat the problem.
 
I have Breverb on other projects and haven't noticed this behavior.  Any ideas what may cause that?
 
Thanks!
 
Donny O. Collins