Ignore_malformed not active despite true

[pdanjou]

Hi
I got a mapping for CreateTime field: "CreateTime":{"type":"date","ignore_malformed":true}
but when I try to import some data with a broken CreateTime value I get

curl -XPUT localhost:9200/_bulk --data-binary @/root/data2.json
{"took":1,"errors":true,"items":[{"index":{"_index":"test","_type":"logs","_id":"AVwR_XIPsCkR6L8Aamj2","status":400,"error":{"type":"mapper_parsing_exception","reason":"failed to parse [CreateTime]","caused_by":{"type":"illegal_argument_exception","reason":"Invalid format: "2017-05-15 15:38:53+02:00" is malformed at " 15:38:53+02:00""}}}}]}

I am a beginner so I might be missing something obvious here.

Thanks for any help

[pdanjou]

from my mappings: "CreateTime":{"type":"date","ignore_malformed":true}