See

Issue is that interfaces are being selected, and then a few hours or a day later, they are set to not collect (unticked). This is a new issue since upgrading from 29 → 30.x

e.g. from the forum post

We have a Cisco device that has 210 interfaces, so only selected interfaces are selected for Collection. I need to monitor two specific interfaces, and when I select the Collect option next to them in the "Choose SNMP Interfaces for Data Collection (inside Manage SNMP Data Collection per Interface), it collects data for a couple of hours and then it stops monitoring it and the Collect check box is unticked. The collection goes back to some kind of default and only those interfaces selected before are now collected. This worked until version 29. This started since upgrading to our current version 30.0.4. It is running on CentOS Stream release 8.