In the wild most royals lay eggs in a 2 week period. That means the breeding season is triggered across the range by an environmental change. Many breeders do not cycle the light and still get breeding so it isn't a light trigger and I know others whom do not change temps and still have breeding. That leaves humidity. the rainy season marks the end of breeding and if there is rain or no rain the rivers and basins fill with water and the average RH goes up. I have no idea if this is the trigger but it as a possibility of it and may have some influence. I notice during our winter with central heating even in a RH controlled room mine either stop feeding of slow down less aggressive feeding. The summer comes and the humidity increases and presto they mostly start again. Aggressively in some cases. My big female whom has been kinda iffy on eating pokes at the FT rat for a while and noses about before striking if she does. She is back to hitting like a freight train. Last night she struck so hard she broke the hind legs of a rat (F/T) I was offering her. I am just guessing but if it helps ...
Sometimes the 'teenagers' just go off for no reason and for long times. Nothing you do will get them to start until they are ready, then watch the fingers... LOL