The TWO game never used : ask_question, so there was no downside to using ? as the prompt character. If you are using ask_question, then clearly there should be a different prompt for the question and the prompt itself. Garry's workaround is good, but I'll actually tweak the TWO theme to not alter the system default ">" character as the prompt character, and the "?" character as the question char.
This will make it's way into the next release of Adventuron, which is scheduled for after this jam ends. There will be a few little cleanups as of this release based on feedback and observations.