Looking at the leases shown using show dhcp server leases, it only shows the leases created or renewed since the last execution of the kea cleanup script.
On execution of this script (that is running once every hour) the lease table will be emptied from /config/dhcp/dhcpv[46]-leases.csv and merged into /config/dhcp/dhcpv[46]-leases.csv.2. This makes entries not show inside show dhcp server leases.
prior to cleanou script execution:
dhcp4-leases.csv: address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state,user_context,pool_id 10.20.0.128,4c:fc:aa:6e:0d:10,01:4c:fc:aa:6e:0d:10,86400,1706452978,1,0,0,tesla,0,,0 10.20.0.129,24:6f:28:0b:7f:40,01:24:6f:28:0b:7f:40,86400,1706453151,1,0,0,peis,0,,0 10.20.0.101,4a:2e:a6:6f:97:47,01:4a:2e:a6:6f:97:47,86400,1706455364,1,0,0,,0,,0 10.20.0.101,4a:2e:a6:6f:97:47,01:4a:2e:a6:6f:97:47,86400,1706455486,1,0,0,,0,,0 10.20.0.102,00:1d:94:0a:6a:3f,,0,1706365590,1,0,0,,0,,0 10.20.0.102,00:1d:94:0a:6a:3f,,86400,1706455592,1,0,0,,0,,0
after execution:
dhcp4-leases: address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state,user_context,pool_id
looking into the dhcp4-leases.csv.2 file before and after reveals that all entries from dhcp-leases.csv are merged into dhcp4-leases.csv.2 during this cleanup.