When it gets warmer, I find the same thing with some species like H. coronatus, O. peruviana (although this is the first time I reared them, they are speeding up noticeably now that its warm out), Cilnia, and Stagomantis. Parasphendale and Miomantis for some reason pretty much grow the same rate all the time, depending on how much you feed them - they just drink more when it's hot.
One thing I am noticing with the Cilnia, that the ones that grow the fastest are A. often the females, which is reverse of normal, and B. tend to die for no apparent reason (just drop dead). Anyone else have this problem with Cilnia?