Jooq batch insert with custom field binding

I have following problem with batch insert:

dslContext.batch(
        dslContext.insertInto(
            TABLE,
            FIELD_1,
            FIELD_2,
            FIELD_3,
            FIELD_4_TS_VECTOR
        ).values(0L, "", "", "")
            .onConflictDoNothing()
    ).bind(value1, value2, value3, value4.toTsvector())
     .execute()

Where toTsvector is:

private fun String.toTsvector() =
    DSL.field("to_tsvector('simple', {0})", this)

In this case it seems DSL.field is not working as expected because instead of binding it just returns value and execution of this query fails with:

org.jooq.exception.DataAccessException: SQL [insert into "table" ("field_1", "field_2", "field_3", "field_4_ts_vector") values (?, ?, ?, ?) on conflict  do nothing]; Batch entry 0 insert into "table" ("field_1", "field_2", "field_3", "field_4_ts_vector") values (100500, 'value2', 'value3', 'value4') on conflict  do nothing was aborted: ERROR: column "field_4_ts_vector" is of type tsvector but expression is of type character varying

But if 'usual' insert is used everything works fine:

dslContext.insertInto(
            TABLE,
            FIELD_1,
            FIELD_2,
            FIELD_3,
            FIELD_4_TS_VECTOR
        ).values(value1, value2, value3, value4.toTsvector())
     .onConflictDoNothing()
     .execute()

Thanks!