I believe what you are seeing matches the behaviour explained here: UPDATE: V1.2.1 node-red-contrib-cron-plus scheduler (incl solar events and Timezone support) - #46 by Steve-Mcl
I believe what you are seeing matches the behaviour explained here: UPDATE: V1.2.1 node-red-contrib-cron-plus scheduler (incl solar events and Timezone support) - #46 by Steve-Mcl