Distorted Audio after Save

After making a save in MainStage, the sound becomes extremely distorted (Local MainStage instrument or AU Plugin). If I quit MainStage and restart, then the sound quality is repaired. If I go into preferences and change my audio source, apply the change, and then change back to the FireFace and apply that change, the audio is also restored. Unfortunately the issue also happens if I switch to any patch with a high number of channel strips, and sometimes—more frighteningly—with a low number of channel strips. Even a reset audio function (like used to appear in Logic, I believe) would allow me to script an "audio panic" of sorts just to re-establish the digital handshake between the interface and the application. It could be a memory allocation issue, in which case a dump feature would be nice.

My system:

•Mac Mini || OS X Yosemite (10.10.2) || Processor 3 GHz Intel Core i7 || Memory 16 GB 1600 MHz DDR3

•FireFace UCX with updated firmware, and the newest drivers (3.26); connected via Thunderbolt to Firewire adapter; on AC power

•MainStage is on its most current version, in various configurations (MultiThreading on/off; Cores set high/low; Kontakt running or not; DFD in Kontakt on/off in Kontakt; Virtual memory active/disabled in MainStage).

Issue did not exist on older Mac Minis with Firewire port, which ran bus powered. But then I was also using an earlier version of MS3, often on OS X 10.9. I'm not in a place to test a thunderbolt connection on a 10.9 machine, but if someone else could report their experiences I might be willing to downgrade the machine I have here.