Crash when displaying Drone on iPhone

[cx20]

I tried to display Drone in Grimoire.js and the browser crashed.
Three.js and Babylon.js are displayed without problems.
The environment I tried is iPhone 6 + Safari.
Perhaps the cause is probably because Grimoire.js has more memory usage than Three.js and Babylon.js.

The following is the result of investigation of memory usage in Chrome on PC.
Three.js glTF Loader + Drone result:

Babylon.js glTF Loader + Drone result:

Grimoire.js glTF Loader + Drone result:

glTF model:
Buster Drone by LaVADraGoN - download 3D model - Sketchfab
https://sketchfab.com/models/294e79652f494130ad2ab00a13fdbafd