Kunenas login will point to CBs, but I think you can disable it in Kunena entirely (can't recall where). Does remember me work from CB login module and just not from the Kunena login? Joomla handles the remember me usage, CB just passes that remember was checked to Joomlas login function.
Ensure within Extensions > Plug-in Manager that "System - Remember Me" is enabled. Also note Joomlapolis is not on J2.5 so please do not expect them to behave the same as it's a different version compared to yours and remember me is entirely handled by Joomla.
Doing a quick search on the issue you can find links like the following to see why remember me may not be working for your site.
stackoverflow.com/questions/11956186/remember-me-plugin-is-not-working-on-joomla2-5