My wife and I bought our WiiU in October of 2013, but we didn't actually set it up until Hyrule Warriors came out. We've been chipping away at Hyrule Warriors since it has come out with absolutely not problems. Today, however, the gamepad has been losing it's connection when you hold the gamepad a certain way...and it's not all the time, either.
The gamepad has been kept in the same place since we started using it, it has not been dropped, and it has been kept charged when not in use, for the most part. There have been no changes to our other electronics, either. We were playing (my wife on the gamepad, me on a controller) and the gamepad needed to be charged. It started happening after she plugged it in. It has been fully charged since then, but it keeps happening when you hold it at a certain angle. I can't seem to get it to do the same thing each time.
I spend some time with it, and was sitting facing the TV and using the gamepad. I would hold it straight at the TV and it would be fine, then I would tilt it up (the screen of the gamepad facing me) and the sound would cut out. If I kept it that way, it would lose the connection. If I tilted it back toward the TV, it would be fine again.
I've checked the sensor bar, and it's plugged in fine (same as it has been). I checked all the connections, but nothing has changed there either. I don't get what happened.