GDB successfully steps through a C++ program one time. After that, attempting to step through program drops me to assembly view of ntdll when I hit cout or other library call.

Steps:

1. Make a new Plain C++ Project
2. Add code:

   #include <iostream>
   
   using namespace std;
   
   int main()
   {
       int x = 5;
       cout << x;
   
       return 0;
   }
   

   #Put break point on first line of main.
   #Build/Start debugger. Hit step over twice. Works as expected, produces output in goodRun.txt attached.
   #Restart debugger. Hit step once, fine. Hit again on cout line (or other library call), and get dumped into ntdll dissassembly - no way to continue tracing code in original project. Debugger output in badRun.txt attached.

Any run after the first produces the drop to assembly. After making a new project, it will run debug correctly once as well, then get weird.

Tried clean builds, manually deleting everything but .cpp and .pro files, restarting QTCreator, doesn't matter. Once I run a project one time it will not debug correctly on future runs.

I have observed this behavior on multiple machines.