Query failed: ERROR: character with byte sequence 0xc2 0x96 in encoding "UTF8" has no equivalent in encoding "WIN1250"

Hi, all.

I need help.

pg_exec(): Query failed: ERROR: character with byte sequence 0xc2 0x96 in
encoding "UTF8" has no equivalent in encoding "WIN1250"

It is a strange. First there was a database with latin2 encoding.

to this database connect an aplicaton with "set client encoding to win1250"
and manipulating data

then database was dumped with pg_dump -E UTF8

then database was restored pg_restore on another cluster in database with
UTF8 encoding

then application connect to new database with "set client encoding to win
1250"

and - query failed

How in this scenario could invaid  characters reach the database ???

And how to solve this ? Errort message is not very useful, because does not
provide any hint (at least column and row)