After defeating ender dragon no xp dropped from it. I believe it went into the portal but when i went it no xp was there.

After defeating ender dragon no xp dropped from it. I believe it went into the portal but after going back to overworld no xp was there it could have despawned but I went back to the end to see if it glitched but no xp was there only one pearl of xp dropped after dragon battle.