Cisco switches and Mikrotik routers missing "Contact" SNMP field in Device Overview

Hey all, first post here! We just started using Libre recently, and noticed that some of our Cisco switches (3550, 3560, and 3560G) and Mikrotik routers (lots of models) don’t have the “Contact” SNMP field in Device Overview, even though they support it in the configuration. Anybody know why that might be?