If you have some other schedulers or data points that use data point pre-sets of ON and OFF the scheduler might erroneously use these pre-sets to schedule instead of the pre sets created for SNVT_occupancy that are based on the allowed ENUM values for the SNVT such as OC_OCCUPIED and OC_UNOCCUPIED as in the picture below.
Note that the additional pre set of OFF and ON have been created and the scheduler will try to schedule these values and not those of SNVT_occupancy with the result that the scheduler will appear not to work.
To work around this, select the line with the additional pre sets, right click and then use the Remove Pres ets option. Do not forget to press submit.
Go back to the scheduler and make sure the schedule values can be selected for the SNVT_occupancy pre-sets.