Problems with jpg export and color profiles

I browsed the forum but I didn't find any recent thread about the issue I'm experiencing right now, I wonder if it's common or it just affects me. Mavericks, Aperture 3.5, all up-to-date.

I imported a RAW file (I tried with both a Nikon and a Sony camera), made a few adjustements and then exported the picture as a jpg. It looked good in the Finder, in Photoshop, in Preview. When I uploaded the file to flickr, everything was ok.

Then, I browsed flickr via its iOS app and - surprise - the image is completely wrong: colors are washed out, desaturated, with an awful greenish dominance. I tried a few things and discovered soon that also opening the file on my Mac with GraphicConverter has the same ugly result. Same with the iOS version of Safari.

I use ProPhoto RGB as my default color space in Aperture. I changed to sRGB: same result. I changed to AbobeRGB and te output is finally consistent through all the platforms and apps.

Too bad I managed to do this only for one photo because, even if I changed the settings, every other photo I exported is still sticking with ProPhoto RGB. The problem is surely here because I solved it changing manually the color space to AdobeRGB with Pixelmator and re-saving the images one by one. But of course this cannot be a successful workflow...

Any experience about this?

Thank you!