SNMP monitoring of FQDN-based nodes

Hello, I'm experimenting with SNMP monitoring of nodes state on our BIG-IP system. Namely, I'm interested in behavior of ltmNodeAddrMonitorState and ltmNodeAddrMonitorStatus fields of ltmNodeAddrEntry objects. While for IP address-based nodes their behavior is mostly clear and in all my tests they are equal, with FQDN-based nodes things are more bizzare.

First, when I initially create FQDN-based node with default icmp monitor and query its status via SNMP, both ltmNodeAddrMonitorState and ltmNodeAddrMonitorStatus return value 28 which is not described in MIB file F5-BIGIP-LOCAL-MIB. Other values are described (like 4=up, 19=down, 24=downManualResume, etc.). So question is, what does this value mean?

Second, when I disable the node, ltmNodeAddrMonitorState changes to "forcedUp", while ltmNodeAddrMonitorStatus stays at 28. But when I enable the node back, nothing changes: that's still "forcedUp" and 28, ltmNodeAddrMonitorState doesn't return to value of 28 like it was initially. Is that an expected behavior?