Update profiler-troubleshooting.md

Add a section for active issues so that the users could track the bug status as we work on them.

Author: xiaomi7732

articles/azure-monitor/app/profiler-troubleshooting.md

@@ -13,6 +13,10 @@ ms.reviewer: mbullwin
 
 # Troubleshoot problems enabling or viewing Application Insights Profiler
 
+## Active issues
+* Profiling for ASP.NET Core 3.x applications hasn't been supported yet. We are working on it. ETA: early March, 2020.
+  * If you have to have Profiler on, a workaround is to use [Application Insights Profiler for Asp.Net Core](https://github.com/microsoft/ApplicationInsights-Profiler-AspNetCore), it is titled for Linux but it works with .NET Core 3.0+ applications on Windows as well. Check out [supported-versions](https://github.com/microsoft/ApplicationInsights-Profiler-AspNetCore#supported-versions) for details.
+
 ## <a id="troubleshooting"></a>General troubleshooting
 
 ### Profiles are uploaded only if there are requests to your application while Profiler is running