My vagrans males go off feed 1-3 times, for short periods of time (2-4 weeks) in the spring and early summer.

One of my vagrans females is really annoying. At the start of the year (typically 1-4 weeks after winter solstice), she starts feeding and continues until early April. Then she stops. Then she throws slugs. Then she eats 2-4 meals in July-August and goes off feed again, and stays off until next year. She's been doing it for the last 3 or 4 years. The temperature in the enclosure is stable, so is the humidity. Only the real world photoperiod varies. I am starting to suspect that the remedy could be a long brumation that fits the real world, which means about 6-7 months, from October to April. Which is almost as long as our wild species brumate and roughly as long as the northernmost T. elegans vagrans populations should brumate (I'm guessing, based on how far south they are compared to us) in the wild.