Auto-channelization is showing inconsistent behaviour on QFX platforms when there is fault on the channels.

On all QFX platforms with auto-channelization enabled on an interface, if a fault occurs on any channels of the breakout channels, the interface switches back to a non-channelized (40G) state, which leads to the link going down.

The below commands can be used to find out indications of faults, errors, or changes in operational status:

show configuration interfaces <interface-name>

show interfaces extensive <interface-name>

show log messages

Nov 25 13:37:42 lab fpc1 dcbcm_port_encap_multi_set unable to determine user port for bcm_port 96

Nov 25 13:37:42 lab fpc1 Non channelized port 51 but non-zero channel number 1

Fix is available via software upgrade:

Resolved-In

junos:21.4R3-S9 junos:22.2R3-S5 junos:23.4R2-S3 junos:24.2R2 junos:24.3R1 junos:24.4R1

https://prsearch.juniper.net/problemreport/PR1799073