In a microservice architecture running on Azure Functions v2 with a consumption plan, we are observing cold starts on services that we cannot explain. These cold starts occur frequently, sometimes within the same minute. Each one introduces a delay of 5-10 seconds. Since these services implement an HTTP-based API, this delay is visible to the end user interface.
We are expecting cold starts when a service has been idle for over 20 minutes or when it's scaling out while experiencing a high load, but every service is warmed up (called every minute or so) and experiences a very light load (under 5%).
We cannot find anything useful in the Application Insights logs.
What could be causing these cold starts? What other information could we gather to help us pinpoint the cause?
Update 1 All services are written in C#.
Update 2 Every service is in its own consumption plan, if that's relevant.
