JUCE is using the keyboard type UIKeyboardTypeAlphabet (a.k.a. UIKeyboardTypeASCIICapable) for the type TextInputTarget::textKeyboard. UIKeyboardTypeAlphabet is deprecated and prevents some international non-ascii keyboards to be included in the selector.
We’re currently working on improving our unicode support, however, until those improvements are done, allowing keyboards to type arbitrary unicode into text editors can result in the wrong glyphs being drawn.
We will update the keyboard type when we are done.