WordPress database error Illegal mix of collations for operation ‘ IN ‘ for quer

I got this error in php-fpm.log
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WordPress database error Illegal mix of collations for operation ‘ IN ‘ for query
SELECT
target.post_id, sum(target.weight * log(96 / least(96, freqs.freq))) as score
FROM
wp_zem_rp_tags as target,
(SELECT label, count(1) as freq FROM wp_zem_rp_tags
WHERE label IN (‘P_6 chi?c h? ?? qu?n ly’, ‘P_file excel qu?n ly chi tiê’, ‘P_làm sao t?o thu nh?p th?, ‘P_làm sao ?? t? do tài ch’, ‘P_l?p trình excel’, ‘P_ph??ng pháp 6 chi?c h?’, ‘P_qu?n ly chi tiêu hi?u qu’, ‘P_qu?n ly chi tiêu v?i exc’, ‘P_qu?n ly ti?n b?c hi?u’, ‘P_qu?n ly ti?n b?c v?i ‘, ‘P_t? phú t harv ecker’, ‘C_tin h?c ?ng d?ng’, ‘A_khon’, ‘A_minh’, ‘A_chi’, ‘A_php’, ‘A_mua’, ‘A_kim’, ‘A_chia’, ‘A_tit’, ‘A_hp’, ‘A_dung’, ‘A_ph’, ‘A_ra’, ‘A_ng’, ‘A_mt’, ‘A_nam’)
GROUP BY label
) as freqs
WHERE
target.post_id NOT IN (‘5196’) AND

target.label=freqs.label AND
target.label IN (‘P_6 chi?c h? ?? qu?n ly’, ‘P_file excel qu?n ly chi tiê’, ‘P_làm sao t?o thu nh?p th?, ‘P_làm sao ?? t? do tài ch’, ‘P_l?p trình excel’, ‘P_ph??ng pháp 6 chi?c h?’, ‘P_qu?n ly chi tiêu hi?u qu’, ‘P_qu?n ly chi tiêu v?i exc’, ‘P_qu?n ly ti?n b?c hi?u’, ‘P_qu?n ly ti?n b?c v?i ‘, ‘P_t? phú t harv ecker’, ‘C_tin h?c ?ng d?ng’, ‘A_khon’, ‘A_minh’, ‘A_chi’, ‘A_php’, ‘A_mua’, ‘A_kim’, ‘A_chia’, ‘A_tit’, ‘A_hp’, ‘A_dung’, ‘A_ph’, ‘A_ra’, ‘A_ng’, ‘A_mt’, ‘A_nam’)
GROUP BY target.post_id
ORDER BY score desc, target.post_id desc
LIMIT 12; made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/hueman-child/single.php’), zemanta_related_posts, zem_rp_get_related_posts, zem_rp_fetch_posts_and_title, zem_rp_append_posts, zem_rp_fetch_related_posts_v2, W3TC\DbCache_Wpdb->query, W3TC\DbCache_WpdbInjection_QueryCaching->query, W3TC\_CallUnderlying->query, W3TC\DbCache_Wpdb->query, W3TC\DbCache_WpdbInjection->query, W3TC\DbCache_Wpdb->default_query

I’ve convert the collation of all my tables in the database to utf8_unicode_ci but no help, the error gone away only I turn of your plugin.
How to deal with this????

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