I am encountering an issue that I have only discovered on devices running on iOS 9.2 with the keyboard extension that I am building. My keys are UIButtons, and the UIButton's title would occasionally not show up. This is especially the case when the keyboard has been previously loaded up in an application (Notes, for example), I switch to another app, and then switch back to Notes. The keyboard would show up with all the rendering, but would just fail to load the UIButton title.
The most frustrating thing is that this only occurs some of the times, and it doesn't have any relationship to memory usage. Here is an image showing the issue:
http://i.imgur.com/UJK0Y0M.png