Caption not displayed in gallery

Hello,

I have a problem with image captions in galleries. When you open any image from gallery, the caption of the image is not displayed. If you go to next or previous image with arrows, those captions are displayed normally, and if you return to the first image that caption is also displayed.

This happens on sometimes on Chrome and Safari. Firefox seems to be working normally.

Any idea what might cause this?

Here a link to example: http://esakon.fi/palvelu/kipsilattiat/