First of all, I've already finished the game before, so I'm not worried about spoilers.
So, I revisited the Ash twin project, took the core out, realized that I didn't have enough time to do anything with it, so I put it back and waited for the sun to explode. When it did, the core warped me to the beginning of the loop again. I decided to go to Dark Bramble to find the Easter egg, but got eaten by an anglerfish. I got informed that I had broken the fabric of time, and got the "You've met a terrible fate" achievement. Then the credits started with Kazoo music.
I'm terribly confused, how did I end the loop? The core is still in the ATP, so how did dying end the loop? Is this a bug?