Missing panels and "Unknown database type" error messages

I am running Grafana via the latest docker image, deployed to our on-prem cluster via Kubernetes and using a persistent volume for the data storage. We are using the default graph panels and the postgres plugin to pull data from our postgresql database. Ocassionally, when loading the webpage we get a missing panel and a message saying there was an error.I set the logging level to debug and I noticed the log is full of “logger=tsdb.postgres Unknown database type= value=”[81 65]"" messages, where the value is a variable length array of numbers. Any clues as to what to check? Thank you.