Arista EOS - CoppSystemEgressTrap drop

On Arista 7280*R* series routers, if you are seeing high # of CoppSystemEgressTrap drop in the output of "show cpu counters queue", the most likely reason is that, there are some packets size are larger than the egress interface configured size. 

smv550.08:42:39#show cpu counters queue summary | nz
Aggregate CPU counters:
This indicates the sum of port-dependent queue counters across all input ports.
CoPP Class                                Pkts             Octets           DropPkts         DropOctets
Aggregate
-------------------------------------------------------------------------------------------------------
CoppSystemBgp                            14358            1141461                  0                  0
CoppSystemEgressTrap                     10688           97079104             228017         2071078411

Arista EOS - %HARDWARE-3-DROP_COUNTER_ALERT, DchUnreachables

What does the following log message mean?

May 15 15:45:42 bn302 EventMgr: %HARDWARE-3-DROP_COUNTER_ALERT: Persistent Internal Drop 'DchUnreachables': 792271126642 detected on Fe3600-3/1

And there is high # of drop in the output of "sh hardware counter drop"

bn302.jhm.mlagB.profA0.w.15:47:58#show hardware counter drop
Summary:
Total Adverse (A) Drops: 20098028670058
Total Congestion (C) Drops: 0
Total Packet Processor (P) Drops: 72029
Type  Chip         CounterName                    :           Count : First Occurrence    : Last Occurrence
--------------------------------------------------------------------------------------------------------------
A     Fe3600-4/2   DchUnreachables-1              :    103285456899 : 2018-05-15 15:34:55 : 2018-05-15 15:35:07

Basically when the LCs are not ready and up, the Fabric modules don't know where to forward the packets, they will drop them and increase this counter. It is quite common during system booting up.