From what I know, japanese letters and general symbols they use start from 0x3000.

[deltoro05]

          From what I know, japanese letters and general symbols they use start from 0x3000.

I used https://symbl.cc/en/ to try few different ranges and see what results I'll get.
Keep in mind I kept using MS Gothic font, so many characters were shown as squares (but behavior of those squares were different)
0180 range - Latin Extended - do not have problems whatsoever
0370 - Greek characters - no problems
Arabic-like languages skipped, since they're right-to-left and symbols appear at start of filename despite being typed in the end
0e00 - Thai - no problems
1800 - Mongolian - no problem, except font drawing changes for whole filename, if there are visible Mongolian characters in line. If characters are cut off (left panel made narrower) - font returns to normal
1E00 - Latin Extended Additional - My font cannot show them, but squares do not jump around as I change panel width, and I believe they would show fine if I used compatible font
2c60 - Latin Extended-C - same as above
2E80 - CJK radicals - the problem I mentioned appears.

Basically, to replicate this you can:

1. set font to something supporting japanese (if you use random font, japanese character would still be shown using substitute font and won't be consistent with ascii characters)
2. create folder/file named "世界中のあらゆる情報を検索するためのツールを提供しています。さまざまな検索機能 を活用して、お探しの情報を見つけてください" (random string from google)
3. change Far panel width using alt+left, alt+right and see how file name behaves. If it's shorter than file panel - then everything is alright. When you shrink the panel, letters are being compressed too forcefully and in the end you have to enable monowidth to be able to distinguish characters

Originally posted by @AndyScull in #739 (comment)