Pinpoint the 5 second interval*

It looks like a research group found a security vulnerability that they then used to find a single common key in all of the cards made by this company. The second part here is a reasonable concern, but the article calls the vulnerability a backdoor in the beginning, which I think is fairly misleading.

Was the aurora once-in-a-lifetime? It seemed like typical-ish solar maximum stuff, which happens every 20 or so years. Was there something special about those specifically?