Incompatibility with media library grid mode

Hi,

We have just discovered a very strange problem when uploading images to the media library (we are using Real Media Library). We have some users who have the Author role. Sometimes, they receive an error message when uploading images : “You don’t have permission to attach files to this post”. However, this only happens when they upload using Medias | Media Library | Add button and when they are in grid mode. List mode is OK. If they use the Media | Add menu directly, there’s no problem anyway. This doesn’t affect users having the Editor role or more generally accounts having the edit_posts capability. Strange !

The problem disappears if I disable One User Avatar. We are still running WP 5.9.5 + Elementor (latest) + Astra (latest) + RML (latest).

Thanks in advance.

Patrick