After Effects expressions breaking with time‑remapped pre‑comps in Bodymovin export

I am working on a client project for a UAE based company called wheelsonrent.ae. . The video needs to explain their business in a clean and modern way, and part of the requirement is to export certain animated sequences from After Effects into Lottie JSON format for integration inside their mobile app.

The issue I am facing is that when I use Bodymovin to export, some pre‑comps with track mattes and nested shape layers render incorrectly. The alpha channels are not preserved and the animation either disappears or shows solid blocks instead of the intended transparency. I have tried different render settings, flattening layers, and even converting shapes to paths, but the problem still occurs.

This is very technical and I could not find any working solution on YouTube or other tutorials. Has anyone experienced this specific issue with track mattes and nested pre‑comps not exporting properly to Lottie, and is there a reliable workaround?