Thanks so much for your responses.  I believe the issue is isolated to one agent but will confirm.  Also I will check into timeout and other options.
Below please find the entries from the T-server logs surrounding the incident.
message RequestUnregisterAddress
	AttributeReferenceID	1402
	AttributeThisDN	'22001'
	AttributeControlMode	0
@12:48:48.9310 [gctmi] Distributing request RequestUnregisterAddress
@12:48:48.9310 [tsgctm] Address [22001,tDN,sIDLE] reqUnregisterAddress
@12:48:48.9310 [gctmi] request RequestUnregisterAddress ctiRefId -1 removed from reqMgr
@12:48:48.9310 [0] 8.1.201.21 send_to_client: message EventUnregistered
	AttributeEventSequenceNumber	00000000000289eb
	AttributeTimeinuSecs	931000
	AttributeTimeinSecs	1522946928 (12:48:48)
	AttributeThisDN	'22001'
	AttributeReferenceID	1402
2018-04-05T12:48:48.931   Trace   CONP-IS-PSRV057   tlh_ccm_tserver_812_p   GCTI-00-04542   EventUnregistered sent to [876] (00000014 tlh_gad_764_4 10.41.8.74:59333)
@12:48:48.9310 [tsgctm] Address [22001,tDN,sIDLE] (clientDisconnected)
@12:48:48.9310 [tsgctm] AgentLogin [22001,id0271,sNRDY] softAgent: sending triggered logout.
@12:48:48.9310 [gctmi] Distributing request RequestAgentLogout
@12:48:48.9310 [tsgctm] AgentLogin [22001,id0271,sNRDY] softAgent: sending logout.
@12:48:48.9310 [gctmi] AgentLogin [22001,id0271,sNRDY] distributing EventAgentLogout
@12:48:48.9310 [gctmi] AgentLogin [22001,id0271,sNRDY] processLoggedOut
@12:48:48.9310 [gctm] AgentLogin [22001,id0271,sNRDY] Changing state to 0
@12:48:48.9310 [gctmi] request RequestAgentLogout ctiRefId -1 removed from reqMgr
@12:48:48.9310 [0] 8.1.201.21 distribute_event: message EventAgentLogout
	AttributeExtensions	[53] 00 01 00 00..
		'AgentSessionID'	'H0LG0DL0TT4UPAAMNFA2BFAHAC0011D4'
	AttributeEventSequenceNumber	00000000000289ec
	AttributeTimeinuSecs	931000
	AttributeTimeinSecs	1522946928 (12:48:48)
	AttributeThisDN	'22001'
	AttributeAgentID	'0271'