[Observium] CE No RRD Updates Since Upgrade to 20.9

I run two instances of Observium. Professional is installed at the office and CE is installed in my home lab.

I followed the steps to upgrade CE (I know, everyone says that) in my lab from 19.8 to 20.9 on November 8 and none of the graphs have updated since. I have rebooted, checked permissions, verified all expected services are running, etc. Reviewing the event log in the Web UI and the logs on the server all show activity. The timestamps of the individual RRD files are updating every time poller runs - just nothing happening in the UI. Can someone help me think of anything else to check?

CentOS 7.9 MariaDB 10.3.27-1 PHP 7.2.34 (OPcache Enabled)

Thanks, Scott