Adapted from MDN: developer.mozilla.org/en-US/docs/Web/SVG/Element/textPath
I know that SVG and textPath especially are not common on the web, but they're essential in OpenStreetMap's iD editor.

Each letter is two chars long: e + accent: ééé
On Safari, I see the accent slightly too far left of the e. I think that they are appearing as separate characters.

Namaste - नमस्ते - is 6 chars long (individually: न म स ् त े). You can tell that the vowel marks and a combining mark are rendered incorrectly if the dotted circles appear in text.
Strangely, the text appears to have the correct width.
This bug was reported to us in September 2018

أستراليا (Australia) is 8 chars long (individually: أ س ت ر ا ل ي ا).
We expect the baseline to have two parts, and the alif with hamza on top (أ) appear at the right of the word. In Safari, the letters are displayed separated, and in left-to-right order.
This bug was a (Chromium issue from 2014) which Chrome fixed in their new system in fall 2021. We currently work around it with client-side text shaping (Arabic presentation forms Unicode block) but this isn't possible for Hindi and other South Asian scripts with combining characters.