Hi, sorry for late reply.
I created a sample post: https://blog.zahidefe.net/test-deneme-bla/
In my html code, first image’s url is starting with http, and second image is starting with https.
This url that I share with you is cached content and first image is serving over http in cached version. But if you add ?sbp_disable=1 query parameter, you’ll see non cached content and in that none cached version, RSSSL works well and I get https for first image too.
If you need any further information I can provide.
Best Regards,
Mustafa Zahid Efe