QFX5120-48YM CRC errors reported on interfaces during vMotion of VMs between ESXi hosts connected

• High-rate CRC errors
• Packet truncation Issue (egress packets/bytes not reaching the line-side PHY)
• Issues appeared after upgrade from Junos 22.2R3.15 → 23.4R2-S5.8
• Only observed on three QFX5120-48YM (Pyrite) switch (in two specific racks)
• All three affected leafs switches in the specific racks used industrial-grade Flex optic 25G-LR optics connected to ESXi hosts
• Issue was only seen on leaf switches in two racks which were equipped with Industrial-Grade 3PO optics (80 units per rack, 160 in total).
• No issues observed on other rack switches using non-industrial-grade or other third-party optics 
• No issues observed on QFX5120-48Y (Onyx) platforms after the same upgrade. Industrial-Grade optics were not present on QFX5120-48Y.

user@switch> show interfaces et-0/0/18 extensive | grep CRC

Carrier transitions: 0, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0

CRC/Align errors 2817 0

Issue was found related to Industrial grade third party optics used on these switches, it was suggested to use supported non-industrial-grade third party optics or Juniper Optics.