Hi @dblvd,
Unfortunately you can only have 1 board per a page. I appreciate we provide a shortcode which can sometimes give off the impression you can put it anywhere you want as many times as you want, but the shortcode has been designed once per a page and the reason for this is performance. IdeaPush is pretty resource intensive, especially with the pro version and the search and idea suggestion etc. to be having multiple instances of the boards on a page is just not efficient for a persons browser. So you will encounter javascript issues when trying to have multiple boards on the 1 page.
What I would recommend as an alternative, is having a main index page which lists the board names and these link off to individual pages each with their own board shortcode.
Or alternatively you may want to consider building or getting someone like me to build you a custom display to show ideas from multiple boards on 1 page, but with watered down functionality so loading etc. is reasonable for users. I hope that helps ??