I have been playing survival mode, not cheating. Yesterday I threw a Ender Pearl in the End Gateway Portal. I wanted to go to the outer island. After threw, the color of The End's sky around me . I can not walk, but I can heard the sound and saw the end snowflakes. Waited a while still can not, then I saved exit the game. But when I entered again, load strip went to the end, and can not enter the game. Two days in a row.           

The Ender Dragon was killed months ago. I to and from the Main World, the main islands and the outer islands many of the times. I created another map for that, and repeated to do it, and so did the result. But today I created another map again and try it again, and the result was normal.

This problematic survival map has been playing for nearly a year, very good. I do not want to delete the map and do not want to copy the seeds. Is this Bugs? Will it be okay? What should I do? Please fix it quickly， Thanks.