exportfs : unable to unexport root individually

Issue

Individually unexporting root fails :

[root@rhel8 ~]# exportfs -i -o rw,sync 172.23.1.247:/ 

[root@rhel8 ~]# exportfs -s
/  172.23.1.247(sync,wdelay,hide,no_subtree_check,sec=sys,rw,secure,root_squash,no_all_squash)
/opt/mydir/subdir  172.23.0.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,ro,secure,root_squash,no_all_squash)
/opt/mydir  172.23.0.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,ro,secure,root_squash,no_all_squash)
/opt/mydir/subdir  *(sync,wdelay,hide,no_subtree_check,sec=sys,rw,secure,no_root_squash,no_all_squash)
/opt/mydir  *(sync,wdelay,hide,no_subtree_check,sec=sys,rw,secure,no_root_squash,no_all_squash)

[root@rhel8 ~]# exportfs -v -u 172.23.1.247:/
exportfs: Could not find '172.23.1.247:/' to unexport.