It is normal to turn on the power amplifier last during the turn-on sequence, and to turn off the power amplifier first during the turn-off sequence. This is to protect the power amplifier and the speakers from warm up thumps from the preamp and sources.Apparently those pops can damage the amplifier if the voltage spike is of sufficiently high voltage and duration. See question 7 here:https://www.hypex.nl/faq/ (The question refers to a tube pre-amp. My preamp is a solid state SHD unit, so not the same conditions. But the point remains that it is better to enable the power amp after the pre-amp has stabilized.)
The Ghent casework seems to have very small holes in the lid, to allow heat to convect up and put of the case. I happen to have used one of their cases with similarly small holes a few years ago for housing an IcePower module, and I enlarged most of the lid holes in a pattern on my drill press because they looked too small too me the way they came from Ghent. It's still working after several years.