There are bug in snmp_traps.c
Line 394-395

Now:
  if (trap_msg->snmp_version == SNMP_VERSION_2c) {
      struct snmp_obj_id snmp_trap_oid =  { 0 };  /* used for...
Need:
  struct snmp_obj_id snmp_trap_oid =  { 0 };  /* used for ...
  if (trap_msg->snmp_version == SNMP_VERSION_2c) {

An OID is created, a pointer is written to it in varbind[1].value.
The memory will be cleared when we leave the curly braces, and the snmp_varbind_len structure will be located in the same place. When calculating the length of varbind[1].value is corrupted.
(In         snmp_trap_varbind_sum
and snmp_asn1_enc_length_cnt)