To add to this.
The problem seems to have happened around june 26. On both my tile server and cycle map as well as other. But I can confirm that I never saw the problem directly on the Standard rendering.

I just created a new server and did a fresh import of a small dataset around that area.
Using my own theme shows the island just fine.

Is it possible that I have updated my database using a daily diff that had “wrong” info in it and somehow I am up to date as I do daily update but i never received the changeset that fixed it?
If I make any sense