Recently I came across this exchange:
Person A: Ja ne.
Person B: Mata aou.
Person C: Ja ne. Mata itsuka.
Real casual till that last line. I've been told that "itsuka" is a way to express uncertainty.
1. Does this make the exchange bittersweet, despite the casual tone of both speakers?
2. Can 'mata itsuka' be used in casual Japanese?
3. Does it infer that the speakers will or will not meet again?
Thanks in advance~!