demo · v138

Letter-spacing ignored in cursive scripts

Drag the slider. The English line spreads as expected. The Arabic line stays joined — Chrome 138 ignores letter-spacing on cursive scripts, where inserting tracking would break joining and harm legibility.

Chrome 138+ should keep cursive scripts joined while applying letter-spacing only to non-cursive runs.
0px

Latin (letter-spacing applies)

The quick brown fox jumps over the lazy dog.

Arabic (cursive — should NOT space apart in Chrome 138+)

الثعلب البني السريع يقفز فوق الكلب الكسول

Devanagari (also cursive)

तेज़ भूरी लोमड़ी सुस्त कुत्ते के ऊपर कूदती है।

computed letter-spacing applied to all rows: 0px
visual outcome: Latin spreads, cursive scripts keep their joining glyphs intact.

the code

p { letter-spacing: 8px; }
/* Pre-138: the Arabic 8px-spaced glyphs broke their cursive joins,
   producing a stuttering result. From 138, the browser silently
   ignores letter-spacing on script systems where it would harm
   shaping (Arabic, Devanagari, Thaana, etc.). */

see also