I just tested (running build 1051; new subs engine; XP SP3) with "rum, eng" as "Default subtitle language" and ... I cannot confirm
adicoto's problem.
Romanian subs pre-checked; the English are not.
You didn't test with a previously played movie and "Remember movie settings" selected by any chance?
(I also had to deselect "Download only if local subtitles are not available", otherwise it would meanwhile find sufficient subs on my HD because of previous testing.)