The bug is reproducible only when the TimePicker is bound to a nullable type (be that DateTime or TimeOnly). In this case, selecting time from the popup includes seconds in the value - the seconds from the time of selection. When typing in the input, seconds are always 00.
The issue is that the user is not aware of the seconds' value and cannot change it. This may lead to a variety of problems - e.g. filtering by time in Grid: https://blazorrepl.telerik.com/cebaGNlH53mOoiaA12.