apple watch open water swim gps tracking errors

When I use my Apple Watch 5 to track my open water swims it (and my friend's as well) has an error at the start every time -- it has us start where we are starting but then there's a green streak that jigs in some random direction before it picks us up again.

As a result my distance logged is further than I actually go and this messes up my split times as well.

((In the first photo I posted I swam straight to the upper right at the beginning, not doing any of that green loop; in the second screenshot I swam straight, not back towards shore as the green streak indicates.)

How to fix this?