Is it possible for NTP to have two system peers at the same time?

In some rare cases, ntpq -p reports here that it has two system peers, like this (IPs and results anonymized):

     remote           refid      st t when poll reach   delay   offset    disp
==============================================================================
*1.2.3.1         .IRIG.           1 u    1   16  377     0.10   -0.012    0.05
-1.2.3.2        4.5.6.7           2 u    3   64  377     0.11    0.014    0.06
+1.2.3.3        4.5.6.7           2 u    5   64  377     0.12   -0.016    0.07
*1.2.3.4        4.5.6.7           2 u    7   64  377     0.13    0.018    0.05
-1.2.3.5        4.5.6.7           2 u    9   64  377     0.14   -0.020    0.06
+1.2.3.6        4.5.6.7           2 u   11   64  377     0.15    0.022    0.07

So there are two servers listed with an asterisk in front, which marks them as "system peers".

Is this actually valid (ie. having multiple system peers), or is that an error in the ntpd or ntpq program?

And if this is a valid situation, I wonder what is the actual stratum of this NTP client in this case - does it have stratum 2 or 3?