filebeat -> es，offset 在一定范围循环重复，多次发送相同内容

利用 filebeat 直接收集日志到 es 集群，运行了一段时间后突然出现 offset 在一定范围内循环，导致重复发送相同的 log 内容，不知道是否有大神知道原因。且 debug 模式报错内容为：
2018-10-09T19:35:50.377+0800 DEBUG [elasticsearch] elasticsearch/client.go:525 Bulk item insert failed (i=0, status=500): {"type":"exception","reason":"java.lang.IllegalArgumentException: java.lang.IllegalArgumentException: field [logtime] not present as part of path [logtime]","caused_by":{"type":"illegal_argument_exception","reason":"java.lang.IllegalArgumentException: field [logtime] not present as part of path [logtime]","caused_by":{"type":"illegal_argument_exception","reason":"field [logtime] not present as part of path [logtime]"}},"header":{"processor_type":"date_index_name"}}