Unicode question

I have similar settings for Netsurf on Iyonix and ARMX6 and, for example,
a UTF-8 encoded file of Cyrillic characters displays correctly on both.
But Wikipedia's nav bar language lists differ.

Having deleted RUfl_cache, Iyonix shows all correctly except Georgian

ARMX6 showed all correctly except
Korean, Japanese, Thai and Chinese
until I deleted RUfl_cache, and now shows none of the non-Latin scripts.

Why the differences? Indeed how come only Acorn fonts are apparently
needed in Netsurf Choices? Setups are:

Iyonix OS 5.24
ARMX6 OS 5.25 (25-Apr-2018)

FontManager 3.79
FontDir Pro 3.23 (ARMX6 only)
Netsurf 3.10 (Dev CI #4851)
Netsurf Choices Fonts:
- Homerton
- Trinity
- Corpus
- Sassoon
- Pembroke
- Sans-serif
Unicode fonts available (but not specified to Netsurf) include:
- Cyberbit
- DejaVu (ARMX6 only)

--
Bernard