Minecraft end bug

This is a non-moded bug, and A minecraft pc bug.

I recently defeated the enderdragon (in creative mode)

And when I defeated the "enderdragon" The end lagged or froze

I don't know why this happened...

(PS: I bought this computer a couple months ago)

when it was frozen, the enderman froze too, but I wasn't frozen I could still break blocks but I could not get OUT of the end! After that I relogged and everything was back to normal!

World: SuperFlat, Presets: Tunneler's dream

Username: Hmm465_Gaming