Read the saving exception
Netflix says audio and subtitle preferences are not saved when most Kids titles are viewed from an adult profile, while they are saved from a Kids profile. A language returning on the next play can therefore involve the profile and title category, rather than an app failing to store every setting or an account having been reset.
Record the actual context
Note which profile is active and which title was used when making the selection. A family may have several profiles with similar names or pictures. Do not change a child’s maturity controls just to reproduce a language-setting observation; the person responsible for the account should preserve the intended viewing restrictions.
Use the documented preference route
Netflix also documents profile audio and subtitle language settings and gives a separate suggestion for persisting an adult profile’s preferred audio using an appropriately rated title. That suggestion should be applied only within the account holder’s legitimate viewing context. It is not a reason to play unsuitable content for a child or bypass the chosen profile arrangement.
Check the next eligible title
Compare the resulting preference on a title for which the desired track is actually available. A saved preference cannot make every programme provide that language. If the behaviour differs from Netflix’s current instructions, report the profile type, exact titles and selected options without sharing the account password or changing unrelated household settings.
Questions, answered
Does Netflix document a Kids-title exception on adult profiles?
Yes. It specifically qualifies saving preferences in that context.
Should maturity controls be loosened merely to test a language preference?
No. Preserve the intended profile and viewing rules.