Unfortunately, this is the current limitation of the SourceMap format. With the regular function, it works fine just because all the variables inside the regular functions are compiled into JS variables with the same name, but with the suspend function, some of the variables are translated into StateMachine's fields.
The situation with the debuggability of suspend functions should be much better when the ticket (
https://youtrack.jetbrains.com/issue/KT-63038) arrives in the next version of the compiler.