there were complaints that Icinga Core 1.8.0 would replace spaces with pluses in several macros. Actually, this was identified as production critical bug, and fixed this evening. You’ll find a test case at #3397 as well. In order to stay safe, I’ve uploaded a quickfix 1.8.1 release – packagers will update their packages shortly.
Sorry for the inconvenience, but keep in mind – more (beta) testers are needed! Check the nightly builds, git and occasional beta releases and report back to your development tracker 🙂