[warning]Can\'t find loc string for key: CorrelationIdForARM

There appears to have been some change introduced by Microsoft that started prompting these warnings when using App Service-related steps. In my case, we use separate steps to first stop, deploy, then start an App Service, and each one of those steps contains at least five of these "warnings." We don't do anything advanced either, just simple deployments; no slot swaps, no ARM templates, just .NET Core code deployment.

Microsoft appears to have heard our complaints and already reported "we have merged the fix for the issue." Not sure how long until we will see that fix implemented however, as it appears to be more of an annoyance rather than something that breaks builds.

https://developercommunity.visualstudio.com/content/problem/859513/azure-app-service-manage-warnings.html

They just announced the solution for this is being deployed and should be fixed for all accounts by the end of the week:

Hi, the fix for CorrelationIdForARM warning is already merged and is under deployment. It should reach all the accounts by the end of this week. Thankyou for your patience.

Source: https://github.com/microsoft/azure-pipelines-tasks/issues/11996