Never had this happen. But here is a much better idea then using the built in recorder for many reasons.
Use a different app. I use tascam PCM, Auria, or garage band. The benefits of using something like these is that when recording, or just checking levels, you have some sort of visual feedback showing a signal. If something was wrong, like in your recordings, you would have seen no signal in the app. Another andvantage is the ability to playback from the app. The built in dl recorder has no playback. So there is no way to test what you are actually getting on your recordings. With other apps you can just playback and make sure things are set up right. Also if you return the recordings to the iPad channel set to 0db then you can get an exact playback of what you just recorded. This way you can get a partial virtual soundcheck. There are many other advantages to using other recording apps. Editing, applying effects, mastering tool kits, iCloud. The biggest thing is the immediate access to your recordings. Then,using the recording app, you can do what you want depending on what the program can do. And all in the iPad.
Moral of this post: Don't use the mater fader built in recorder.