Yes, it has to be fixed.
You can bring back your last rendering by going to Rendering > Rendered Frame Window - this will show you standard 3ds Max VFB with your most recent rendering.
Another idea is to use floating interactive rendering window instead of docked one (render setup > scene > start interactive). This will show interactive VFB. To switch to regular rendering, just click on "stop", then "render" again. To run interactive rendering again, click and hold on "render" button, and pick "start IR".