This design choice is necessary because Android keyboards aren't just keyboards, they're input method editors. Software receiving simple codepoints as input works great on English desktop computers where every inputtable character can be neatly laid out on a QWERTY keyboard, but when it comes time to support more complex languages or even autocorrect it usually devolves into a hacky mess
It’s definitely a bug, because the design choice they made breaks invariants and causes buggy behaviour in otherwise functioning code.
Otherwise it would be like saying “segfaulting randomly is actually not a bug, but rather a side effect caused by a design choice we made to have sloppy code and terrible memory management”.