DPU Neighbor resolve is flaky after config reload.

[dypet]

On smartswitch platform, noticing that DPU neighborship does not always resolve after config reload. It is intermittent, after 4344 it occurs less frequently, however I was able to reproduce it after multiple config reloads (~8 in this case). Tables being checked:

admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB keys "*" | grep NEIGH_RESOLVE_TABLE | grep 20.0.200.1
NEIGH_RESOLVE_TABLE:Vlan55:20.0.200.1
admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB KEYS "*" | grep NEIGH_TABLE | grep 20.0.200.1
NEIGH_TABLE:Vlan55:20.0.200.1
admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB HGET NEIGH_TABLE\:Vlan55\:20.0.200.1 neigh
9c:38:18:e3:1e:2f
admin@MtFuji-dut01:~$ sonic-db-cli ASIC_DB keys "*" | grep NEIGH | grep 20.0.200.1
ASIC_STATE:SAI_OBJECT_TYPE_NEIGHBOR_ENTRY:{"ip":"20.0.200.1","rif":"oid:0x600000000058f","switch_id":"oid:0x21000000000000"}
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ sudo config reload -y
Acquired lock on /etc/sonic/reload.lock
Disabling container and routeCheck monitoring ...
Stopping SONiC target ...
Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db
Running command: /usr/local/bin/db_migrator.py -o migrate
Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment
Restarting SONiC target ...
Enabling container and routeCheck monitoring ...
Reloading Monit configuration ...
Reinitializing monit daemon
Released lock on /etc/sonic/reload.lock
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ date
Wed Jun 17 04:15:43 PM UTC 2026
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ date
Wed Jun 17 04:20:53 PM UTC 2026
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ 
admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB keys "*" | grep NEIGH_RESOLVE_TABLE | grep 20.0.200.1
NEIGH_RESOLVE_TABLE:Vlan55:20.0.200.1
admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB KEYS "*" | grep NEIGH_TABLE | grep 20.0.200.1
admin@MtFuji-dut01:~$ sonic-db-cli APPL_DB HGET NEIGH_TABLE\:Vlan55\:20.0.200.1 neigh

admin@MtFuji-dut01:~$ sonic-db-cli ASIC_DB keys "*" | grep NEIGH | grep 20.0.200.1

In this case it did not resolve after 5+ minutes.

[prsunny]

@zjswhhh for viz