Turtles not Laying Eggs, Mother just Wanders Ocean

I can't get turtles to lay any eggs in the Nintendo Switch version of the game. I know the mechanics of breeding with home beaches and all (I've successfully done it on the XBox 360 version) - I locate some turtles, feed them sea grass, they mate, one grows larger, and then the would-be mother dives into the ocean and just wanders around aimlessly, often just spinning around in a circle. I've tried multiple pairs of turtles in various beaches, but got the same result with every one of them.