Mine have kicked into breeding with the cooler weather and season change. Summer they didn't, it was too hot here. AC's and fans may simulate the cool air but the shrimp don't buy it, it just helped keep them alive and bacteria down. Since the first cool weather hit and my tank dropped 6 degrees naturally, its been molts and berries a lot more for my CRS.
Mine are this way too. I had no berried female until just the last 2 months. Now I have 2 batches on the ground and at least 3 females berried up. I hope they continue! ;-)