When using the PM profile setting 'trigger on shutdown' the software doesn't look at the dates specified on the shutdown it is supposed to be triggered by. Instead it triggers the work orders however many days is specified on the 'days in the future' tab.
This is not a bug.
When manually generating PMs the PM Generation dialog has 2 attributes named the same but behave differently and this can lead to confusion. The attributes are both called "Days in the future" on the PM Generation Profile in the "Work order generation options" section.
Whereas the Due Date triggered "Days in future" is indeed a Planning Horizon, the Shutdown triggered "Days in the future" is an event start date.Because these two fields appear to be identical, end-users may believe that the Shutdown triggered "Days in the future" is also a planning horizon that will trigger all work due to be triggered up until that time. This is not the case, this attribute actually sets the work orders' Planned start date.
We have launched an enhancement request (082702) to change the label of the Shutdown "Days in the future" to read "Planned start date of Shutdown" which should improve the clarity of what this attribute is used for.