From the display settings:
In the blood pressure reading form (date is June 3rd)
App (on Android), is "Jun 3" and current time displayed is 21:44 (24h).
Different browser (Chrome) does use the format as expected:
Is this relaying the same in your Connect app? If you clear your cache or try a different browser does that setting change?
What browser are you using where it does not accept that time format?