keisatsu

Probably not. It's most likely automated scanning and the subdomains seem common enough to be included in wordlists. Another possibility is that the subdomains have leaked somehow, do you use LetsEncrypt? If so, the existence of your subdomains is public knowledge and can easily be picked up by bots.

I had issues until I got connectors that come with a little sleeve that you thread the wires through before putting them into the part you clamp them in. Get those if you if you haven't already. Also get a cable tester, they are pretty cheap