Thanks for the info!
I have the exact same problem (Surface 2, newest updates) Unregistered device SE is on any single sleepstudy report up to the last date I get information on (january 17th, 2015).
I can not generate a sleepstudy report for some reason because I get this: “An unexpected error condition has occurred. Unable to perform operation. You may not have permission to perform this operation.” And yes... I am doing the report "in admin mode" so that's not the case... This problem seems to be another issue with some guy having a workaround (he wrote an exe file solving the problem) which we can not use with our RT devices (because of the .exe file).
Anyway... I have a huge battery drain during the connected standby. In 10 hours more than 30%... so every night I lose about that amount of battery power just because of this annyoing issue... Because of my sleepstudy report not working any more I can not say what exactly is draing my battery most, but I am pretty sure it is Unregistered device SEbecause of it being on every single sleepstudy report before...
I love my Surface 2, but this just annoys me!
Microsoft do something!!!
And I don't mean some rediculuous "solutions" like refreshing and so on... we can clearly see (after more than 7 pages of dicussions about this issue) that's not going to help...
I sure hope that update the tech person was talking about (@l.whitmarsh) is "real"...