OSX Photos Exporting

Hi! Whenever I am trying to export a bunch of photos (usually to a temporary folder on my desktop) from Photos (version 1.3) app on El Capitain I am getting a percentage of the photos exported half picture half white (not necessarily exactly half), as if it suddenly stopped exporting. This issue occurred after the last update of Photos. I need to mention my photos are RAW and trying to export to JPEG (95% of the time at least).

This is really frustrating as I need to then look for the problematic pics and try to re-export them (does the trick but it is time consuming and I shouldn't resort to this).

Would really appreciate your help. Anyone encountered this issue? How do I solve it?