This issue might been seen if the following conditions are meet:
Standalone vme port IP addresslab@EX4600-standalone> show interfaces terse | match vme vme up upvme.0 up up inet x.x.45.34/26
When FPC0 is Master & FPC1 is Backuplab@EX4600-VC> show virtual-chassis Mstr Mixed Route Neighbor ListMember ID Status Serial No Model prio Role Mode Mode. ID Interface0 (FPC 0) Prsnt XYZ123 ex4600-40f 129 Master* N VC 1 vcp-255/0/221 (FPC 1) Prsnt 123XYZ ex4600-40f 129 Backup N VC 0 vcp-255/0/22
lab@EX4600-VC> ping x.x.45.34 count 100 rapid PING 1x.x.45.34 (x.x.45.34): 56 data bytes....................................................................................................--- x.x.45.34 ping statistics ---100 packets transmitted, 0 packets received, 100% packet loss
When FPC1 is Master & FPC0 is Backuplab@EX4600-VC> show virtual-chassis Mstr Mixed Route Neighbor ListMember ID Status Serial No Model prio Role Mode Mode. ID Interface0 (FPC 0) Prsnt XYZ123 ex4600-40f 129 Backup* N VC 1 vcp-255/0/221 (FPC 1) Prsnt 123XYZ ex4600-40f 129 Master N VC 0 vcp-255/0/22
lab@EX4600-VC> ping x.x.45.34 count 100 rapid PING x.x.45.33 (x.x.45.34): 56 data bytes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!--- x.x.45.34 ping statistics ---100 packets transmitted, 100 packets received, 0% packet lossround-trip min/avg/max/stddev = 0.046/0.371/2.780/0.313 ms