Lucanidae help

I've just started raising beetles, my understanding is that when a grub pupates, it remains in a hibernating state until
it emerges as an adult for mating and or eating.
Perhaps the beetle was prematurely awakened.
I've also found with adult beetles, if they don't act normally, they don't come out of it and expire prematurely.
Many of us trade non-natives, typically lepidoptera, and it's a risk, and without knowing the source, or how it was shipped,
perhaps an answer lies there, accepting risk with non-natives is a personal choice, and typically all goes well, I have very
much wanted to import live exotic beetles and decided against it, they pose different issues than ova or pupa.

Not enough people raise beetles, it takes a lot longer to get them from an egg to an adult than lepidoptera.
I raised my first grub to adult Lucanus elephus recently, over a year from the l2 I purchased.
Experience takes time, other than that, books and asking for help.
Try Orin McMonigle's book- (the ultimate guide to raising beetles), covers our natives and exotics.