When I put in: Today at 13:30, it shows that my reminder is set for Today at 6:30am instead of what I typed in.
I've been able to reproduce this issue and have forwarded it to the developers.
Thank you very much for reporting it and sorry for any inconvenience it might have caused you.
I am having the same problem. I notice that the difference in the number of hours between what I enter and what I get as a result is the same as the offset in my timezone. (-5, central time). I hope this helps.
this issue has been fixed. Reminders should now display the correct due time.