jit.movie objects can't read more than 625 videos (except with PhotoJPG)

Hello, when trying to read more than 625 videos (cf patch below), Max returns an error "jit.movie * error loading file xxx.mp4".
After experimenting for several weeks, I am noticing that the limitation occurs for all codecs except PhotoJPG.
I have tried with different versions of Max, different video engines, different videos, resolutions, codecs, frame rates, lengths, and I always get the same results.

Here is the patch I am using to test this.
Main patch:

poly~ patch called "Poly_jit.movieEmpty"

Anybody could help me understand why this is happening?
Is this a limitation of Max? But why would this work with PhotoJPG and not H264 nor ProRes?
I have tried with two instances of Max and each one can load 625 videos for a total of 1250, so this does not seem to be a limitation of my GPU.
Unfortunately with the confinement, I am unable to test this on another computer, so I would really appreciate help!
thanks
Florent