Yesterday I did the same lab, hehe, same results.
R2#show ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(1)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 192.168.1.1 Fa1/0 167 00:17:51 81 486 0 17
R2#
*Sep 11 19:02:43.279: EIGRP: Received QUERY on FastEthernet1/0 nbr 192.168.1.1
*Sep 11 19:02:43.279: AS 1, Flags 0x0:(NULL), Seq 18/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0
*Sep 11 19:02:43.283: EIGRP: Enqueueing ACK on FastEthernet1/0 nbr 192.168.1.1 tid 0
*Sep 11 19:02:43.283: Ack seq 18 iidbQ un/rely 0/0 peerQ un/rely 1/0
*Sep 11 19:02:43.287: Handling TLV: 242 43 for 0 route: 1.1.1.1/32
*Sep 11 19:02:43.295: EIGRP: Sending ACK on FastEthernet1/0 nbr 192.168.1.1 tid 0
*Sep 11 19:02:43.295: AS 1, Flags 0x0:(NULL), Seq 0/18 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 1/0
*Sep 11 19:02:43.299: EIGRP: Enqueueing REPLY on FastEthernet1/0
R2# nbr 192.168.1.1 tid 0 iidbQ un/rely 0/1 peerQ un/rely 0/0 serno 13-13
*Sep 11 19:02:43.303: EIGRP: Requeued unicast on FastEthernet1/0
*Sep 11 19:02:43.315: EIGRP: Sending REPLY on FastEthernet1/0 nbr 192.168.1.1 tid 0
*Sep 11 19:02:43.319: AS 1, Flags 0x0:(NULL), Seq 18/18 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/1 serno 13-13
*Sep 11 19:02:43.387: EIGRP: Received ACK on FastEthernet1/0 nbr 192.168.1.1
*Sep 11 19:02:43.387: AS 1, Flags 0x0:(NULL), Seq 0/18 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/1
R2#show ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(1)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 192.168.1.1 Fa1/0 171 00:18:03 78 468 0 18
Very good observation of you.
Thanks again. 