In 4.2, my playlist remaining shows the way I want, and is set to nn:ss in Playlist1 --> Display in Config.
However in 4.3 build 1819, I get the PC formatting, in my case US 12 hr am/pm, see attachment.
I imported the config from 4.2 when I installed 4.3 fyi.
In fact, there have been some changes lately (also in the latest v4.2 builds). When you click that field, you can toggle through the three available display modes:
End of playback - should be displayed in the time format determined by the current locale
Remaining duration - in hh:nn:ss format
Total duration - in hh:nn:ss format
So perhaps what you see is the display in “end of playback” mode? You can hover with the mouse over the field and see that the tooltip says, it’s pretty verbose.
Ah, yes, I have End of Playback! Although I have US defaults I much prefer the 24hr clock, however I leave AM/PM as my wife prefers that! I will use Duration as it gives me a good guide when I do a VT session and mixdown.