Drawer Menu Font display error

Hi Everyone,
I am facing an issue with one of our Bible apps. Translation is done using 3 different scrips and fonts.
For one of the scripts we noticed display issues, which are present only in the Drawer Menu and Content Menu Title bar.
This is only happening when the Tamil scripted interface language is selected, but for the other 2 scripts everything is displayed correctly.
Translation text (body) is displayed perfectly in all 3 scripts.
I tried to set the interface language to use the right font and also the User Interface Style, but nothing worked so far.

Is it possible that the issue is with the font?
Have you added font(s) that support all the Tamil characters?
Or are you relying on the system fonts?

Can you report what specific fonts you are using? Note that woff fonts are not (completely) supported, so you have to use ttf fonts. See Using woff2 fonts, not applying to song lists.

I do not expect that the font is causing this, as the same font is used for the text body and there it is displayed correctly.
This is a TTF font called “TAMLThiruValluvar-Regular.ttf”.
The app contains 3 different fonts (manually added), one for each script that we are using.

I personally suspect that the Builder somehow uses the System font for the Menus and Title bar and not the fonts that have been added manually. Can somebody confirm this ?