I have had one of these viewport issues where I can´t remember exactly when it started happening and I cannot recall what I touched for it to stop working as usual.
I cant figure out how to make my Camera view to adjust to the aspect ratio of the camera, it seems to be locked in 1920x1080, and the crop handle is missing as well. I have tried playing with the viewport settings, the aspect ratio settings but nothing. I have compared all the settings from a fresh scene that works and nothing seems out of order.
Look for a render settings or Karma node to change the resolution or aspect ratio. if one exists in the chain, then it overrides the aspect ratio on the camera.
