I think this is the same issue:
https://github.com/Taracque/RaidPlanner/issues/13
I’ve tried to make a workaround in RaidPlanner, but it seems it still not working (or CB 1.8.1 broke this).
Community Builder issue can be found here:
http://forge.joomlapolis.com/issues/3341
marked for 1.8.2 version.
Anyway thanks for the report I’ll check it once again, maybe there is another way to fix it.