NTP source keeps changing

Hi.

On one of the Linux client (Centos 7.9), I see few times that NTP source keep changing. This is only VM in this environment, so I can't compare it with other VMs.

Time stays correct, it is just NTP servers/source which is changing. Is it indicating something, or I should check something why it is happening ? Is it expected behaviour of NTP ?

Code:[root@net-vols ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
+lserver-gpsc001 .GNSS. 1 u 6 16 377 0.074 +0.004 0.003
*lserver-gpsc001 .GNSS. 1 u 5 16 377 0.074 +0.003 0.009
-lserver-ntp001- 192.168.70.137 2 u 4 16 377 0.143 -0.027 0.006
+lserver-ntp002- 192.168.70.137 2 u 3 16 377 0.152 +0.059 0.008
[root@net-vols ~]#
----------------------
[root@net-vols ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*lserver-gpsc001 .GNSS. 1 u 10 16 377 0.077 +0.001 0.008
+lserver-gpsc001 .GNSS. 1 u 8 16 377 0.052 +0.004 0.008
-lserver-ntp001- 172.27.21.70 2 u 8 16 377 0.144 +0.142 0.010
+lserver-ntp002- 172.27.20.70 2 u 7 16 377 0.138 +0.130 0.019
[root@net-vols ~]#If I login to lserver-ntp001, then I see this --

Code:[root@lserver-ntp001 ~]# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
-172.27.20.70 .GNSS. 1 u 368 1024 377 0.128 -0.150 0.025
-172.27.21.70 .GNSS. 1 u 957 1024 377 0.145 -0.129 0.021
172.27.4.70 .NONE. 1 u 67 1024 377 11.951 -109554 0.044
172.27.5.70 .NONE. 1 u 67 1024 377 12.016 -109554 0.029
+192.168.70.16 .GPS. 1 u 106 1024 377 62.252 -0.096 2.944
+192.168.70.17 .GPS. 1 u 1023 1024 377 61.042 -0.048 2.301
*192.168.70.136 .GPS. 1 u 428 1024 377 52.352 -0.031 0.013
+192.168.70.137 .GPS. 1 u 883 1024 377 52.356 -0.064 0.044
[root@lserver-ntp001 ~]#Thanks