Quite often when I get a mail from a "bad" action, the %reply% is empty. FOr exmaple I check for free disk space, but when the mail arrives the number of megabytes is blank, when the error is corrected, it always display in the "good" action, can you look at it and see if you can figure it out.
I have seen the problem in diskspace, Commited bytes and filesize
HostMonitor uses exactly the same code to start "good" and "bad" actions. What status of the test when Reply value is empty? Probably status is "Unknwonw"? It means HostMonitor cannot retrieve information, that's why Reply value is empty.