This is a common occurrence for me since I don’t have much time to play. I often get about halfway through and then stop playing for months. When I come back to it I always want to start from the beginning and then the cycle happens again.
One example for me is Fallout 4
Fallout New Vegas and Fallout 3. Must’ve played them 100 times by now without ever finishing them… I also didn’t finish fallout 4, but don’t care about it.