As discussed on call, below is the summary:

> The MX interface was down after upgrade of peer EX device.

> On both side, the interfaces were showing detached in lacp & down physically

> The optics power was fine in both side - MX et-0/0/7 & EX et-0/0/50.

> We tried enable/disable of port on both side, with no success.

> Upon swapping AOC optics between et-0/0/7 & et-0/0/12 at MX, the et-0/0/07 came up & et-0/0/12 went down.

> Hence we swapped them back & replaced the optics with new one on et-0/0/7.

> Now all ports are up.

This is mostly because of the sudden power surge/change at optics of MX, caused optics failure, which was due to reboot of EX.

Hence in case of another upgrade of connected, you can disable port from peer side before its upgrade.