Time field edit mask problem - Bug in Delphi?

Just a simple question,

I have EditMask := '!90:00;1:_' (and DisplayFormat := 'h:n') for a time
field (Paradox). This mask is the default mask that You can choose from
Input Mask Editor's Sample Masks.

Mask works just fine except when You activate to a already filled field
- Then field seems to show only hour and zeros like is actual time is
15:35 then mask displays 15:00.

Is this some kinda bug or what?