stack of 5 7750s in the core - high cpu after Aruba controller upgrades

[pmonardo]

Hi,

Have a customer where we recently upgraded their core stack of 5 x 7750 to 8095f, no issues there, running smoothly. 

Customer then upgraded their pair of Aruba controllers from 8.6.0.15 to 8.6.0.18 and now the CPUs of the 7750 stack are hitting 99% utilisation. 

I am trying to debug this and wondering what could have caused this. We unplug the aruba controllers, CPU returns to normal...

I have a show CPU log before and after, some dm commands and a tech-support 

Any thoughts on how to troubleshoot this to see what is causing the spike?