Bubble letter sorting does not work properly with other languages?

This issue seems like another Bubble’s bug, Letter Sorting is working fine with English letters but not for other language, in my case Thai.

I’m trying to sort my RG from A-Z
From The Example, no matter how much you add the A to the input box,
it will always sorting from A to D as I expect. because A is the first Letter.

but it’s working differently when I’m trying to do a letter sorting from Thai letters,
the more letter I add to the box, the box will be much lower on the list,
even it’s a first letter of the alphabet.

The Editor

thanks