Yes. On the Canon G1 X, this behavior can be caused by Safety Shift being enabled.

Safety Shift lets the camera override your selected exposure setting when it thinks a correct exposure can’t be achieved with the current limits. In Tv mode, that can mean the camera lowers your chosen shutter speed in low light instead of strictly keeping 1/500s.

If you want the camera to respect the shutter speed you set, disable Safety Shift in the menu. Then the camera should keep your selected shutter speed rather than dropping to something like 1/30s.

If the scene is still too dark after that, you’ll need to accept underexposure, raise ISO manually, open the aperture as much as possible, or add more light.