A problem with convert to Avro in QuaryDatabaseTable Nifi

[#1]

Hello everyone,
My NIFI pipeline gets data from DB2 using QuaryDatabaseTable processor. When I launch it get exception (org.apache.nifi.processor.exception.ProcessException: Error during database query or conversation of record. I found out that the problem with some char in a table's field. I see this in the nifi log (nifi-app.log) and I see there that it falls with an exception java.nio.charset.UnmappableCharsetException: Input length = 1.
What I tried. I used another JDBC connection driver. I tried to set UTF8 in bootstrap.conf and nifi-env.sh (I found this tip here). It has not helped. 
Could you help me, please?

[#2]

Sorry, I forgot to specify the NiFi version. We use 1.11.4

[#3]

Seems like db2 is using some data type which is not recognizable to Avro. You can try to Disable Avro logical types to false in QueryDatabaseTable and then parse the data correctly within the flow.

If you find the answer helpful please accept this as a solution.

[#4]

Thank you for your answer.
Yes, sure I tried this option. I know exactly which field is causing the problem. I even know the symbol. The field has char type. I tried to apply UTF-8, but it didn't help

[#5]

Is it possible to show what the character is exactly? With logical type string it should accept any character as long as is it not a invalid or garbage value....