Yes — this is normal if long exposure noise reduction is enabled.

After a longer shutter speed, the camera may make a second exposure of the same length with the shutter closed. This records sensor noise/hot pixels so the camera can subtract them from the actual image. During that process, Live View stays unavailable, so the screen remains black and the camera won’t return immediately.

So a 2-second exposure can be followed by roughly another 2 seconds or more of processing before Live View resumes. The click you hear afterward is the camera returning to its normal Live View state.

If the delay is inconvenient, you can disable long exposure noise reduction in the camera settings. The tradeoff is that you may see more noise or hot pixels in longer exposures.

Also note: Live View can shut off automatically after a period of inactivity to save battery, which is separate from the post-shot delay.