Secondary standby LSP is down due to the error, 'CSPF: Can't find non-overlapping path'.

Primary and secondary standby LSP are using the same exit interface.

When the primary and secondary standby LSP are using the same exit interface, secondary standby LSP remains down. It gives a computation error for the secondary standby LSP. 

user@router# show protocols mpls 
label-switched-path R1-R5 {
    from 1.1.1.1;
    to 5.5.5.5;
    inter-domain;
    primary R3;
    secondary test {
        standby;
    }
}
path R3 {
    3.3.3.3;
}
path test {
    3.3.3.3;
}
interface ge-0/0/1.0;
interface ge-0/0/2.0;

[edit]
user@router# run show mpls lsp extensive 
Ingress LSP: 1 sessions

5.5.5.5
  From: 1.1.1.1, State: Up, ActiveRoute: 0, LSPname: R1-R5
  ActivePath: R3 (primary)
  PathDomain: Inter-domain
  LSPtype: Static Configured, Penultimate hop popping
  LoadBalance: Random
  Encoding type: Packet, Switching type: Packet, GPID: IPv4
*Primary   R3               State: Up
    Priorities: 7 0
    SmartOptimizeTimer: 180
    Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 10)
13.13.0.2 S 
    Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
          13.13.0.2 35.35.0.2
   17 Mar 30 04:18:47.318 Self-ping ended successfully
   16 Mar 30 04:18:46.839 Record Route:  13.13.0.2 35.35.0.2
   15 Mar 30 04:18:46.839 Up
   14 Mar 30 04:18:46.839 Self-ping started
   13 Mar 30 04:18:46.839 Self-ping enqueued
   12 Mar 30 04:18:46.511 Originate Call
   11 Mar 30 04:18:46.511 CSPF: computation result accepted  13.13.0.2
   10 Mar 30 04:18:46.508 Clear Call
    9 Mar 30 00:36:14.072 Self-ping ended successfully
    8 Mar 30 00:36:13.638 Selected as active path
    7 Mar 30 00:36:13.623 Record Route:  13.13.0.2 35.35.0.2
    6 Mar 30 00:36:13.623 Up
    5 Mar 30 00:36:13.622 Self-ping started
    4 Mar 30 00:36:13.622 Self-ping enqueued
    3 Mar 30 00:36:13.280 Originate Call
    2 Mar 30 00:36:13.280 CSPF: computation result accepted  13.13.0.2
    1 Mar 30 00:33:15.156 CSPF failed: no route toward 5.5.5.5[6 times]
  Standby   test             State: Dn
    Priorities: 7 0
    SmartOptimizeTimer: 180
        No computed ERO.
    1 Mar 30 04:55:48.186 CSPF: Can't find non-overlapping path to 3.3.3.3[57 times]
  Created: Mon Mar 30 00:29:50 2020     
Total 1 displayed, Up 1, Down 0

Deactivating primary LSP:

[edit]
user@router# deactivate protocols mpls label-switched-path R1-R5 primary R3  

[edit]
user@router# commit 
commit complete

Once primary LSP is deactivated, secondary LSP is UP.

user@router# run show mpls lsp extensive 
Ingress LSP: 1 sessions

5.5.5.5
  From: 1.1.1.1, State: Up, ActiveRoute: 0, LSPname: R1-R5
  ActivePath: test (secondary)
  PathDomain: Inter-domain
  LSPtype: Static Configured, Penultimate hop popping
  LoadBalance: Random
  Encoding type: Packet, Switching type: Packet, GPID: IPv4
*Standby   test             State: Up
    Priorities: 7 0
    SmartOptimizeTimer: 180
    Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 10)
13.13.0.2 S 
    Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
          13.13.0.2 35.35.0.2
    9 Mar 30 04:57:36.516 Self-ping ended successfully
    8 Mar 30 04:57:35.887 Selected as active path
    7 Mar 30 04:57:35.871 Record Route:  13.13.0.2 35.35.0.2
    6 Mar 30 04:57:35.871 Up
    5 Mar 30 04:57:35.871 Self-ping started
    4 Mar 30 04:57:35.871 Self-ping enqueued
    3 Mar 30 04:57:35.691 Originate Call
    2 Mar 30 04:57:35.691 CSPF: computation result accepted  13.13.0.2
    1 Mar 30 04:57:14.800 CSPF: Can't find non-overlapping path to 3.3.3.3[60 times]
  Created: Mon Mar 30 00:29:50 2020

Once the exit interface of Primary and Secondary LSP is different, Secondary standby is UP again.