Null-coalescing out parameter doesnt give error

This question describes a error related to using Null-coalescing, Null-conditional and out parameter:Null-coalescing out parameter gives unexpected warningThe answer details the reasons for this error.

But when I copy the example from the question to my project, I don't get an error and everything compiles. I encountered the fact that the project is compiled on my computer, but others have problems. Does it depend on the environment? What environment?

Project uses .net5 and С#8.0. I tried VS2022, Rider and console msbuild as compiler, all of them compile successfully.