Link Alarms are not propagated when there is Routing Engine switchover

On RE switchover for ULC platforms link status alarms were not resend to RE and hence the  alarms were not getting raised.
MXA xe-0/0/0:0  <-----------------> xe-0/0/12  MXB

lab@MXA-re0> show version invoke-on all-routing-engines | match :
re0:
Hostname: MXA-re0
Model: mx304
Junos: 23.4R1-S1.5
re1:
Hostname: MXA-re1
Model: mx304
Junos: 23.4R1-S1.5

set chassis redundancy graceful-switchover
set chassis alarm ethernet link-down red



<<<< Initially, xe-0/0/0:0 is up and no link down alarm is seen on master RE >>>>>>
{master}
lab@MXA-re0> show interfaces xe-0/0/0:0 | match xe-0/0/0:0
Jun 15 08:16:17
Physical interface: xe-0/0/0:0, Enabled, Physical link is Up
  Logical interface xe-0/0/0:0.16386 (Index 338) (SNMP ifIndex 583)

{master}
lab@MXA-re0> show chassis alarms
Jun 15 08:16:35
1 alarms currently active
Alarm time               Class  Description
2024-06-14 18:35:07 IST  Minor  FPC 0 firmware outdated

<<<< Make the xe-0/0/0:0 interface down from peer router >>>>>>
[edit]
lab@MXB# set interfaces xe-0/0/12 disable
Jun 15 08:16:59

[edit]
lab@MXB# commit
Jun 15 08:17:01
commit complete

<<<<< Notice xe-0/0/0:0 interface went down and link down alarm is raised >>>>>
{master}
lab@MXA-re0> show interfaces xe-0/0/0:0 | match xe-0/0/0:0    
Jun 15 08:17:11
Physical interface: xe-0/0/0:0, Enabled, Physical link is Down
  Logical interface xe-0/0/0:0.16386 (Index 338) (SNMP ifIndex 583)

{master}
lab@MXA-re0> show chassis alarms                              
Jun 15 08:17:15
2 alarms currently active
Alarm time               Class  Description
2024-06-15 08:17:03 IST  Major  xe-0/0/0:0: Link down
2024-06-14 18:35:07 IST  Minor  FPC 0 firmware outdated

<<<<< Now do a GRES RE switchover >>>>>>>
{master}
lab@MXA-re0> request chassis routing-engine master switch
Jun 15 08:18:37
Toggle mastership between routing engines ? [yes,no] (no) yes
Jun 15 08:18:39

Resolving mastership...
Complete. The other routing engine becomes the master.

{backup}
lab@MXA-re0> request routing-engine login other-routing-engine
Jun 15 08:18:57
Last login: Fri Jun 14 18:28:01 from re0

--- JUNOS 23.4R1-S1.5 Kernel 64-bit  JNPR-12.1-20240207.1947db3_buil
{master}
lab@MXA-re1>
Message from syslogd@MXA-re1 at Jun 15 08:18:59.125  ...
MXA-re1 spmb1 CMLC: Chassis Manager terminated


<<<<< Notice the link xe-0/0/0:0 down alarm disappeared  which is not expected>>>>>
{master}
lab@MXA-re1> show chassis alarms
2 alarms currently active
Alarm time               Class  Description
2024-06-15 08:18:58 IST  Minor  FPC 0 firmware outdated
2024-06-15 08:18:41 IST  Minor  Backup RE Active

<<<< Link is still down>>>>
{master}
lab@MXA-re1> show interfaces xe-0/0/0:0 | match xe-0/0/0:0
Physical interface: xe-0/0/0:0, Enabled, Physical link is Down
  Logical interface xe-0/0/0:0.16386 (Index 338) (SNMP ifIndex 583)

<<<< Now make the link up from peer >>>>>>
[edit]
lab@MXB# delete interfaces xe-0/0/12 disable
Jun 15 08:20:21
[edit]
lab@MXB# commit
Jun 15 08:20:23
commit complete

<<<< Notice the link has come up and no link down alarm is seen as expected >>>>
{master}
lab@MXA-re1> show interfaces xe-0/0/0:0 | match xe-0/0/0:0    
Jun 15 08:20:34
Physical interface: xe-0/0/0:0, Enabled, Physical link is Up
  Logical interface xe-0/0/0:0.16386 (Index 338) (SNMP ifIndex 583)

{master}
lab@MXA-re1> show chassis alarms
Jun 15 08:20:38
2 alarms currently active
Alarm time               Class  Description
2024-06-15 08:18:58 IST  Minor  FPC 0 firmware outdated
2024-06-15 08:18:41 IST  Minor  Backup RE Active

<<<< Now make the link down from peer >>>>>
[edit]
lab@MXB# set interfaces xe-0/0/12 disable
Jun 15 08:20:55
[edit]
lab@MXB# commit
Jun 15 08:20:57
commit complete

<<<<< Notice link has gone down and link down alarm is raised as expected >>>>
{master}
lab@MXA-re1> show interfaces xe-0/0/0:0 | match xe-0/0/0:0    
Jun 15 08:22:09
Physical interface: xe-0/0/0:0, Enabled, Physical link is Down
  Logical interface xe-0/0/0:0.16386 (Index 338) (SNMP ifIndex 583)
{master}
lab@MXA-re1> show chassis alarms                              
Jun 15 08:22:12
3 alarms currently active
Alarm time               Class  Description
2024-06-15 08:20:59 IST  Major  xe-0/0/0:0: Link down
2024-06-15 08:18:58 IST  Minor  FPC 0 firmware outdated
2024-06-15 08:18:41 IST  Minor  Backup RE Active