[Stuckinsofa]

The password is stored in plaintext since they could read it via Kibana but I'm guessing you mean that their identity system which they use to store users store credentials in plain text.

To that I say meh: Could just as well be that they decided to log all Http request to troubleshoot some issue without realizing the security implications. The article even says it was a rolling list of passwords which further indicates loggimg since you probably don't store trace logs forever.