A review of various browsers on desktop and mobile show the Arabic question mark rendered from a system font fall back despite the Adlam font containing the appropriate glyph. This can be seen at the center of the last line in the attached screen grabs. This was briefly discussed during Meeting 7 W3C Font and Text Community Group. (Meeting notes in link) It is possibly related to a script itemization issue where Adlam is not properly recognized.

Chrome Mac OS:

Firefox Mac OS:

Edge Android:

Firefox Android:

Chrome Android:

Sample Inspection results from Firefox showing the question mark is rendered with Times New Roman.