I've added a CSS Style on Business Partner window > Prospect field (is a checkbox) - see attached 2Pack :
InlineStyle = background-color: red!important; font-weight: bold;
DisplayLogic = @IsProspect@ = Y
When the window opens on a record IsProspect = Y, the label is displayed in red and bold (screenshot 1).
If I untick the checkbox, the label is displayed as 'normal' (screenshot 2).
But if I tick the checkbox again, the label is just displayed as bold (still in dark) (screenshot 3).
Opening the record from the Recent Items colorize the label with the right style.
Seems the style is loaded partially (only the "font-weight: bold" is used).
Is easily reproducible using attached 2Pack.