Hi cyrilrueg,
That seems to be a very plausible reason.
Try this: save the file with the problem and use the
File> Save Project with Assets. This typically gives you an "Alert" to find missing Assets.
Of course, the RS Asset Manager has under
File> Relink Assets is the option to find the Assets and create the correct pathway.
Let me know if you get it working.
If you have another follow-up question, please open a new Forum Thread. This will help everyone searching for answers to find things more quickly. Thanks for considering.
My best wishes for your project.