In Sketch mode:
- Sketch a line and keep the cursor at the line's endpoint.
- Click and hold down left mouse button to start drawing a tangent arc from the end of the line.
- Try to zoom in or out using scrollwheel.
- Zoom is locked - it can't be used here while the LMB is held down.
3dConnexion's Spacemouse's knob is also unable to zoom while the LMB is pressed during this action. It's necessary to start and complete this arc at the same zoom level.
Other Sketch tools, like Rectangle, Arc, or Circle do not have this limitation. For example, I can click and hold any Rectangle tool and freely change the zoom while still holding down the LMB.
Running Inventor 2021.1.