"Я хочу обсудить этот вопрос сегодня."
Translation:I want to discuss this issue today.
These are the imperfective and perfective verbs respectively, roughly corresponding to English "to be discussing" vs. "to discuss/to have discussed".
One does not "speak" a question in English. One may "ask" or "pose" a question. Thank you.
Indeed, weird that "I want to ask this question today" was not accepted...
Not weird at all imo. обсудить means to discuss something not to ask something. It is very much possible to discuss a question.
It's not too far meaning-wise, but problem=проблема. I.e., there is a closer Russian match to your sentence, and Duo has a preference for more literal translations (at least when nothing is gained by deviating from them).