Good evening,
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 🙂