Sometimes, and SLO object is not working (related action not executed) when the corresponding Job is executed using the "Recurring" option (C_PERIOD).
It will always work using the "Execute once" option.
Bug identified by Engineering. Will be fixed in a future release.
Release : 12.3
Component : AUTOMATION ENGINE
Will be fixed in a future release.
Workaround : use an alert through the Jobs instead of the SLO object.