Winform objects change their Font after focus

Question

I'm having a weird issue i haven't been able to figure out. For some reason all the text on the main form of my application changes from Arial Bolt (various sizes) to what i think is Arial size 7. This happens as soon as the control gets focus and includes buttons, textboxes and labels. It also happens if i show a second form, then go back to the first one (in this case all text changes). This seemed to me to have something to to with the Focus() or Paint() events, however Focus() events only change the control colour and I don't have any custom Paint events.
To clarify: Any control that has focus resets its font to (what i assume is) default.
The problem seems limited to just the main screen (form1) of this application. I've recently updated the WinEC 7 bsp on my device, which is when i first noticed this issue but i couldn't come up with a reason why. I've spent quite a bit of time on Google looking for possible causes but i've come up empty handed. Anyone have any ideas?