The problem is 100% related to HTTP2 module configuration on APACHE 2. We disable the module, everything works on HTTPS. We enable it, and mainly images (but sometime other resources) are not downloaded. The connection is dropped.
SSL LABS show A grading for the site. The paths NEVER change. The problem is not between HTTP and HTTPS, but between HTTPS with http 1.1 and HTTPS with http2 protocol.
We tried updating Apache to the latest version but nothing. We found an UPCOMING version still on experimental mentioning fixes to HTTP2. Maybe that will help.
The most strange thing for us is why this only affects MAC devices (Safari and iPHONE).