Error when display foreign language for the first time

Question

Am I writing a short story, and I feel most comfortable writing with Latex than any rich-text editor. Yet for the first time I have to use two different languages in my story. French as the main language (my native one), and Tamil (since my story takes places in Tamil Nadu).

But I have an issue that only happens once when rendering my pdf:

And the next time I use tamil everything is fine, I don't have any error compiling my project.

I configured my babel as such

\usepackage[french]{babel}

\babelprovide[
    main,
    import,
    language = Default]
    {french}
\babelprovide[import]{tamil}
\defaultfontfeatures{Scale=MatchLowercase}
\babelfont[*tamil]{rm}{Lohit Tamil}
\renewcommand{\FBthinspace}{\FBcolonspace}

My configuration file is way longer, but I only put the babel part, since most of the rest is from a template.

Also I'm using XeTeX, it seems to work fine with luatex, but I have a timeout when trying to compile with luatex on Overleaf

EDIT: I have a very dirty solution: I added \phantom{\foreignlanguage{tamil}{தாலுகா}} to correct the glitch of the first occurence, don't know why it happens only on first occurence though, but thank you all for your replies

Answer 1

This file seems to compile fine both with XeTeX and LuaTeX engines (after copying the font Lohit-Tamil.ttf in the local directory):

\documentclass[a4paper,french]{article}
\usepackage{fontspec}
\usepackage{babel}
\frenchsetup{ThinColonSpace}
\babelprovide[import]{tamil}
\defaultfontfeatures{Scale=MatchLowercase}
\babelfont[*tamil]{rm}{Lohit Tamil}

\begin{document}

Du texte en français: oui!

\begin{otherlanguage}{tamil}
தமிழ்
\end{otherlanguage}
\end{document}