Hi @djoshi ,
Thanks for reaching out to Q&A.
Usually high CPU utlization would cause performance issues and at times there would be some timeout exception as the function would take longer time to execute. The scaling behavior in consumption plan and premium plan is controlled by the Scale controller. This is responsible to add and remove the number of instances for the function app.
Please note that, the scaling decisions taken by the scale controller are not just based on the CPU/ memory utilization, it is a combination of cpu,memory utlization, incoming load of requests in case of http triggers, number of messages in the queue in case of service bus/storage queue etc. So you will have to check the incoming load and memory utilization along with the cpu utilization.
I hope this answers your question