App services Strange Behavior

I was hoping someone can shed some light on an issue we're seeing.

 

We have a number of app services which will run fine serving requests with an average response time of 0.6 seconds. Randomly throughout the day they response time will spike up to 2 minutes and the site will become unresponsive, 10 minutes later the everything returns to normal.. Looking at the app services we see no spike in requests, CPU and memory is below 30% and queue length is normal.

 

Has anyone experienced anything similar?