I'm not shure that it is a bug, but think that it can be better to implement.
For any test i have action that change test interval (to 50% of current) when test has bad status and restore this interval when test has normal status. Tommorow i was missed with any configuration of action and time interval of the test was changed to 50% of current in bad state and it was changed to 50% agan in good state. So every other time test interval was changed to 00h00m00s (test checks without any interval) and HM was not responding. I think that HM must checks minimum test inteval and doesn't permit set it smaller then one second.