Checkmk Werk 14287: Fix another source for frozen Microcore during config reloads (Addition to #14285)

ID: 14287 Title: Fix another source for frozen Microcore during config reloads (Addition to #14285) Component: Core & setup Level: 1 Class: Bug fix Version: 2.2.0i1 In addition to the werk #14285 we released with 2.1.0p8, this werk fixes another situation which could block the reload of the Microcore. This could happen in case you have notification rules configured which use the match condition "Match only during timeperiod".