Heat is definitely a possibility to check. When my 86U would go into the 90s things would slow down and misbehave. I redid the thermal pads and that brought me down into the 70s. With a fan strapped on I'm in the 40s and forgot about the heat problem.
I'm also puzzling about the routers IP address. When it is working, reserve that address on the main router to fix it there and prevent anything else from getting the address. Don't fix it just on the 86U.
I'm also puzzling about the routers IP address. When it is working, reserve that address on the main router to fix it there and prevent anything else from getting the address. Don't fix it just on the 86U.