After some testing it seems that the plugin you are using to edit po files is not reading the plugin
it is correctly reading other plugins and the theme, but for some reason not reading the CF Portfolio plugin.
I’ve tested on WPML and it’s reading the plugin okay, and the text within.
A solution might be using JS
Please go to the Theme Options >> General >> Advanced
and add jQuery('.circleflip-portfolio.type-circleflip-portfolio .readmore').html('Something >>');