Vietnamese text input accent recognition failure

I a hesitant to put this in the bug reports, but I figure this is still the best place for it. While doing text input for Vietnamese, typing the characters with an accent does not show as correct, including when entering the final word. Copy and paste from the sentence description works as expected, as does input on the android app.

It is possible that the input method I am using, the gnu/linux keyboard, just isn’t compatible, but it would be nice to get some other opinions on this. For reference, the output is as follows

aăâêươ, àảãáạ, òỏõóọ and so on.

( Third image shows that copy and paste functions )