I noticed a few more issues on how language is being used in the Moodle Mobile app. 

Since I have no clue if there is a relationship in what we received as feedback from users, I created a new issue. 

• Moodle 4.1
• Moodle Mobile 4.3.0 
• Languages: Dutch and English 
• Filter MultilangV2 (plugin) and Multilang Moodle core

Reproduction 

1. Verify that you have both multilang filters set to Content and headings on site administration > Plugins > Manage Filters.
2. Create a course with at least:
   1. One section name "Section one" for English and 'Sectie een" for Dutch language. 
   2. A Moodle Page activiteit with name "Page English" for English and "Pagina NEderlands" for Dutch 
   3. Content in Moodle Page for English and Dutch language. 
3. Create a student account with language preference: Dutch
4. Enrol this account as a student to your course
5. Login in the Moodle site with the student account and verify you see everything in Dutch. 
6. Install the Moodle app on a nAndroid phone
7. Login with the student account
8. Check if the language in the Moodle Mobile app is Dutch. 
9. Check if you see the course content in Dutch. 
10. Switch the User profile to English in the website. 
11. Sync the Moodle Mobile app. 
12. Verify that the Course Section and Page activity name is NOT translate to English. 
13. Verify that the course content is translated to Enligh. 
14. Change the Moodle Mobile app language to English
15. Verify that all your content is now in English. 
16. Change the language prefrence back to Dutch
17. Iinstall the Moodle app on an Iphone 
18. Follow the steps 7 to 13 again. 
19. Verify that the language has not changed on your Iphone. 
20. Change the language in your IPHONE settings to English. 
21. Verify the Moodle mobiel app again and notice that the content is showing in English. 

First we though it was the Multilang V2 filter that did not want to change the headings and titles, even though this was set in the Moodle filter settings. 

But we noticed the same with Moodle core filter. 

Then we figured out that changing the language in the Moodle Mobile app, has influence on it - but ONLY on andriod (Samsung S22 & S23) phones. On Iphones students have to ensure the language on their phone is set to the language that they want the app to display. It overrules the Moodle mobile app language setting. 

Our teachers find it very confusing that the Moodle LMS website is acting on the Language preferences and language menu change. But the app is not: 
A) translating the Heading/Titles properly when multi lang filters is being used. 
B) depends on the Iphone setting of the users