Unable to replace an FPC in a 2-member VC setup due to the following commit error observed:

[edit virtual-chassis]

 'member 1'

   Can't have serial number configuration without preprovisioned

error: configuration check-out failed

Mixing non-preprovisioned and preprovisioned configurations, hence the system is throwing an error.

user# show | display set | match virtual-chassis

set virtual-chassis no-split-detection

set virtual-chassis member 0 mastership-priority 255

set virtual-chassis member 2 mastership-priority 245

set virtual-chassis member 1 mastership-priority 245

set virtual-chassis member 1 role line-card

set virtual-chassis member 1 serial-number 12345678

If you are preferring to maintain a non-preprovisioned VC configuration, delete virtual-chassis and add the following configuration during a scheduled maintenance window:

set virtual-chassis no-split-detection
set virtual-chassis member 0 mastership-priority 255
set virtual-chassis member 1 mastership-priority 255

If preferring to have a preprovisioned VC configuration, delete virtual-chassis and add the following configuration during a scheduled maintenance window:

set virtual-chassis preprovisioned

set virtual-chassis no-split-detection

set virtual-chassis member 0 role routing-engine

set virtual-chassis member 0 serial-number <serial-number>

set virtual-chassis member 1 role routing-engine

set virtual-chassis member 1 serial-number <serial-number>

In case the issue is still persisting, please raise a case with JTAC for further assistance.