Search doesn't seem to work properly for non-English languages (at least for Simplified Chinese)

[marchbox]

I have a dataset that the primary language is Simplified Chinese. But when I search with query in Simplified Chinese in the global search or in the reference field search, it's not working as expected, here are some examples when I search with the word "Train" and its Chinese translation "火车":

• [Working] train
• [Not working] 火车
• [Working] '火车'
• [Not working] "火车"
• [Working] “火车” (note those are Chinese double quotation marks)
• [Working] ‘火车‘ (note those are Chinese single quotation marks)
• [Working] 。火车。 (Chinese period)
• [Working] .火车.

Both "train" and "火车" are in a field named title. It's very strange that adding punctuation marks around Chinese word sometimes works.

I'm new to Sanity so I'm not sure what code is relevant that I should paste here, so please let me know. I did add the @sanity/locale-zh-hans package but assuming that's only for localizing the Studio UI.

Thanks in advance!