Microsoft Todo time format not matching OS time format

I know this is a really old post, but I have determined the issue and found a workaround.

The 12h vs 24h option in ToDo is based on the Display Language, not the Region or other Date/Time formatting settings.  

Apparently, Microsoft assumes that people in the US only use 12h clocks.  However, if you set the Display Language to another English variant which commonly uses a 24h clock (e.g. UK English), ToDo will display a 24h clock for setting reminders.

I have seen similar issues with other Windows Store apps, where the app uses regional settings based on the display language instead of the Windows defined regional settings.

Hope this helps.