Can you provide more information?

There was a recent bug report that was similar to this at https://forum.square-enix.com/ffxiv/...Daily-Roulette

In that report, experience that is granted only once is shown twice in the chat box, the first time because they gained it the same way they do when killing a mob, the second time to clarify this was the roulette bonus.

If it's the same as the bug report I linked it's not a bug and is working as intended.