Insufficient memory (case 4)

Anyone know the meaning of this error message, and what can be done to avoid it?

It seems to happen only when I open the Material Editor in a particular DGN file. The file has a couple of complex meshes with 8000x 8000 pix JPG materials assigned (Elevation drape).

This is a high-spec notebook (64Gb RAM, RTX A5000).

Microstation v8i 08.11.09.919

Thanks,

Max