A few of my Imps run warm and drain batteries quickly. Swapping hardware to another Imp001 fixes the problem.
I suspect that at some time I’ve damaged the Imps that run warm by accidentally doing the wrong things like sinking too much current through an IO pin. I’ve not had any Imps fail though.
If you partially fry an I/O then that can cause degraded operation and high power drain.
Got a multimeter? If you power up an imp via an april and have no code running on it, it should be taking in the 70-90mA range on the 5v input, ISTR. If you’re significantly above that then the device could be fried, yes.