Half Duplex alarm is not cleared.
The Half Duplex clear trap should be sent by the switch after the interface negotiates the Full Duplex status. This does not happen because when the interface switches to Down state STP will need to reconverge. As STP will recalculate the tree all interfaces will be in discarding mode and the Half Duplex trap will be dropped.
This happens because the HAlf Duplex Clear trap is not received by eSight.
Disable STP when ever you need to monitor a flapping interface status.