This system preference, ExcludeHolidaysFromMaxPickUpDelay, is explained in the manual as having an Allow/Don't Allow option, however, in the 19.11 version of Koha it has Use Calendar/Ignore Calendar. This will need to be updated in the manual.
I believe Andrew(?) rephrased all the calendar/holiday system preferences, so all of them should be checked.
This has been resolved - the 20.05 manual has the right values.