3 Hour Warm-up?

I have a pair of conrad johnson Premier V mono-blocks that take a minimum of 3 hours to warm up and continue to improve even then. This seems excessively long to me, but when they do finally warm up the sound is ethereal. Until then, the sound is muffled, constricted and excessively warm even for cj. The highs settle in first, the lower mid range is so bloated and diffuse it's really quite unlistenable prior to warm-up. It's hard to believe this is how they are intended to operate but if you guys tell me "that's how it is" then "that's how it is". I guess what I'm asking is: Even though the amps eventually sound great to me, could there be something wrong contributing to the long warm-up?