PT Native 11.1.2 Tempo Change CPU Spike

I'm suddenly getting CPU spikes at tempo changes in Pro Tools 11.1.2 in a VI/Sample library intensive session.



If I remove the tempo change the session plays back at the same location with no problems (CPU peaking around 45%). Add the tempo change back into the session and playback chokes whenever it hits the tempo change and gives me a AAE -9173 error everytime.



This happens regardless of the playback buffer setting.



My session is mostly Kontakt (24 instances, about 150 instruments), two instances of PLAY, a few instances of Addictive Drums, a dozen or so audio tracks, about 25 instances of Altiverb, and a dozen or so other plugins.



Aside form the tempo change issue, this session runs easily on my system -- usually hovering around 45% even with very dense midi programming using lots of heavy libraries (i.e. LA Scoring Strings, Cinebrass, Symphobia, etc etc...).



Anyone experiencing anything similar to this?

I've searched and wasn't able to find similar threads for PT11 -- apologies if I've missed something.



Thanks in advance for any thoughts on this!



Pro Tools 11.1.2



iMac 3.5G i7 32G RAM

System Drive SSD

Sample Drives 4x SSD via Thunderbolt

Work Drive 7200RPM G-Raid via Thunderbolt