I'm not entirely sure what the problem is but here are 3 things that you can try.

(1) I notice that you are currently using Juicebox-Pro v1.4.3.2.
There have been 5 official releases since v1.4.3.2 (the current version being v1.5.1) with many bugfixes. Please see the Version History page for a full list of changes between versions.
I would recommend upgrading your Juicebox-Pro galleries to the current version to see if this helps with your problem.
Full instructions for downloading the latest version and upgrading existing galleries can be found on the Upgrading Juicebox support page.
(You can upgrade an existing gallery by simple swapping its current 'jbcore' folder with the 'jbcore' folder from the latest Juicebox-Pro download zip package ('juicebox_pro_1.5.1/web/jbcore').)

(2) I notice that your 'Urbano' gallery uses slightly different configuration options than your 'Paisajes' gallery (for example).
Try changing your 'Urbano' gallery's 'config.xml' file to make sure that it uses the same configuration options as your other 2 galleries. This might help.

(3) Your 'Urbano' gallery currently has both a galleryWidth of '100%' and a galleryHeight of '100%' (set in the gallery's embedding code) whereas your 'Paisajes' gallery (for example) has a galleryHeight of '100%' but a galleryHeight of '80%'.
Try changing your  'Urbano' gallery's galleryHeight to '80%', in line with your other 2 galleries, in case this makes a difference.
(If a gallery has both a galleryWidth of '100%' and a galleryHeight of '100%' but the gallery's parent containers do not have heights specified by CSS, then Juicebox might determine that the gallery takes up the entire web page (100% x 100%) and the gallery's layout may differ because of this.)

Hopefully these suggestions will help,
Please let me know how you get on and if I can be of any further assistance.