F5 management LDAP auth buggy behavior

We are attempting to integrate an f5 pair with LDAP for management authentication, the integration fails for the first device, however, works fine for the second F5 device.

Both F5 devices are running on the same software version v15.1.3.

The behavior is contradictory on both devices

On device 1:

Case 1:

1 LDAP server is configured and LDAP referral is enabled --> auth fails.

When LDAP(1 server configured still) referral is disabled -> auth succeeds. 

Case 2:

We then tried adding 1 more LDAP server to this device and so:

2 LDAP servers are configured and LDAP referral is enabled --> auth still fails(but this works on device 2)

2 LDAP servers are configured and LDAP referral is disabled --> auth still fails

On device 2: 

Only case 1:

2 LDAP servers are configured and LDAP referral is enabled --> auth succeeds

These articles say LDAP referral should be disabled on v14 and v15 due to a bug, but the behavior is not consistent at all. 

https://support.f5.com/csp/article/K73370247

https://support.f5.com/csp/article/K17311

https://cdn.f5.com/product/bugtracker/ID806093.html