Generated a map on 1.16 and upgraded step by step to 1.18.2.

In parts of the map generated after update to 1.18 (or 1.18.2, not entirely clear) two treasure maps from sunken ships did not lead to chests.

Seed: -154635172

Coords for one map: 330 y 1096

Because my kid was very sad about that I put a chest there myself and buried it for her to find. After opening the chest an achievement popped for her (xbox).