My guess is they understood that they were supposed to generate a random key but didn’t know how to do it properly and instead of using a cryptographically secure method that involves large prime numbers, ended up using a single randomized byte.

Though even that might be more complicated than what they did, because it’s also possible they just manually created them, maybe approaching it as a “this will be a shared resource in this office so let’s make it easy to share”.

Or maybe it was deliberately made unsecure to allow other fuckery, like spying on anyone using one of those keys or using the ability to sign certificates with a trusted cert.