Newly added keyword field is not searchable

ES version: 6.8.x

Hi,

I added 2 new keyword fields to some of my documents (10%) in an index. But those 2 new fields are not searchable. I refreshed the field list from kibana (management -> index pattern -> Refresh button). And in kibana I have green dots in the Searchable and Aggregatable columns for those 2 fields. But whey I try to search them from kibana, or from the dev tool I see no result.
The mapping for those 2 fields is keyword. I double-checked it.

What could be the problem? How can I solve it?

Thanks in advance.