I have 2 identical and empty reports.
Then I add a static text box to the detail band in both reports and apply a global style named "Test" (bold, italic, borders) to both.
In report #1, the text box does not change at all in the designer and when running the report, it shows the style minus the borders.
In report #2, the text box shows everything (bold, italics, borders) immediately in the designer.
Then I try the same with another style, that is exactly the same, but has a different name ("TableHeader"). And with that, it works in both reports.
Attaching both reports and the style template.