Create an article with title in Hebrew
ביו
then purge and run smartsearch indexer (I used snowball as indexer)
When done, enter the title in the search box (still in the indexer page):

we get

500 Illegal mix of collations for operation 'like' SQL=SELECT COUNT() FROM `#__finder_links` AS l INNER JOIN `#__finder_types` AS t ON t.id = l.type_id WHERE l.type_id = 4 AND l.title LIKE '%ביו%' OR l.url LIKE '%ביו%' OR l.indexdate LIKE '%ביו%' Illegal mix of collations for operation 'like' SQL=SELECT l.,t.title AS t_title FROM `#__finder_links` AS l INNER JOIN `#__finder_types` AS t ON t.id = l.type_id WHERE l.type_id = 4 AND l.title LIKE '%ביו%' OR l.url LIKE '%ביו%' OR l.indexdate LIKE '%ביו%' LIMIT 0, 20 Illegal mix of collations for operation 'like' SQL=SELECT COUNT() FROM `#__finder_links` AS l INNER JOIN `#__finder_types` AS t ON t.id = l.type_id WHERE l.type_id = 4 AND l.title LIKE '%ביו%' OR l.url LIKE '%ביו%' OR l.indexdate LIKE '%ביו%' Illegal mix of collations for operation 'like' SQL=SELECT COUNT() FROM `#__finder_links` AS l INNER JOIN `#__finder_types` AS t ON t.id = l.type_id WHERE l.type_id = 4 AND l.title LIKE '%ביו%' OR l.url LIKE '%ביו%' OR l.indexdate LIKE '%ביו%'

Looks like this happens for any non-latin characters