Hello,
I just installed the new One UI 8 on my Galaxy Watch 7 Ultra and added the new watch face "Sporty Classic". I noticed that this watch face displays incorrect moon phase information. The same issue also occurs with the "Heritage Classic" watch face.

However, an older watch face with a similar style — "Rose Gold" — shows the correct moon phase.

I've attached screenshots below to confirm what I'm seeing.

Here you can see the actual moon phase

Here you can see my screenshots from "Sporty classic" (that's also attach on Heritage Classic). And for comparison the Rose Gold watch face, that's work correct.