Input echo question

I can duplicate so wondering if it has already been reported.
 
With multiple (5) tracks.
One audio track with Guitar Rig 4 plug-in
One audio track with .wav drum -one measure looped
3 synth tracks ( Omnisphere, Trilian, Stylus)
 
The repeatable issue;
 
In play changing the the input-echo off and on will drop audible volume about half but
no change in level meters on tracks or master out.
The only way to eliminate/get output volume back to "normal" - close and reopen project.
 
It doesn't happen if transport is stopped before turning input echo on or off.
 
I just want to know if this is already known. "Yes" or "No" only please and thanks.