# Problem overwriting field using json filter plugin

**URL:** <https://discuss.elastic.co/t/problem-overwriting-field-using-json-filter-plugin/299132>\
**Category:** Logstash\
**Created:** [March 8, 2022, 6:35pm UTC](https://discuss.elastic.co/t/problem-overwriting-field-using-json-filter-plugin/299132 "2022-03-08T18:35:48Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [March 8, 2022, 7:39pm UTC](https://discuss.elastic.co/t/problem-overwriting-field-using-json-filter-plugin/299132/2 "2022-03-08T19:39:58Z")

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> [@tstrul](#):
>
> any idea why that happens?

Read [this](https://discuss.elastic.co/t/getting-illegal-state-exception-error-while-pushing-logs-to-elasticsearch/290029/2) thread. You have indexed documents where the [log] field is a string, and now you are trying to index documents where [log] is an object in the same index. That does not work.

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