have tried the following...
power strip with 6ft 14ga cord,
direct outlet with a 3 way plug,
25ft 16ga with a 3-way plug,
25ft 16ga with integral 3-way plug.
wall to 3-way with one LE connected, and an LE connected to a 25ft extension
tried coiling cables to increase inductance
have had the issue 2 seasons now, but 2 seasons ago was a mix of v3, v4, and v5s. There were only a few v5s, so it was not that big of a deal. now that the display is almost all v5s, it is more of a problem when having to go out and reset multiple groups of controllers.
If I stagger the startup, then everything works fine. If I flip on a single circuit to power on 2 LEs on a single cord, it will almost always result in neither LE posting.